This key lime pie is so refreshing and has the perfect balance of tart and sweet. Topped with a dollop of whipped cream – it’s really all you need on a hot summer day.
Inspired by all the key lime pies we ate in Florida – this is our favorite recipe, made the traditional way – with graham cracker crust and creamy key lime juice filling.
This is quite a long article! You’ll find here interesting information about Key lime pie, its history, ingredients, step-by-step photos, photos of pies we ate in Florida, and much more. If you want just the recipe, click on the jump to recipe button!
Key Lime Pie
Key lime pie is made with cookie crust and creamy filling made with key lime juice. It’s the state dessert of Florida and it’s especially popular in the Florida Keys.
This sweet tart reportedly originated in Key West in the late 19th century. There are many theories about where this pie was first created. Some say it was invented by fishermen, who took sweetened condensed milk and key lime juice to their fishing trips, then combined it with eggs, dry crackers, and left on the sun to set.
The use of sweetened condensed milk, an essential ingredient, was common because fresh milk and refrigeration were uncommon in the Florida Keys until the 1930s (adding sugar to milk increases its shelf life).
Another theory states that Key lime pie was not even invented in the Key West (to which most Florida Keys locals would of course disagree!) but in New York as Lemon pie, by the producer of sweetened condensed milk and then popularised in the Florida Keys by swapping lemon juice for local key lime juice. You can read more about Key lime pie history in these articles: Key lime pie history, or here.
Back in the day, Key lime pie wasn’t even baked – the proteins of the egg yolks, condensed milk, and the acidic lime juice curdle, thickening the filling without baking. Today, key lime pies are usually baked to pasteurize the eggs and thicken the filling further (it sets better after being baked).
What are Key limes?
Key limes are limes that grow in the Florida Keys, Caribbean, Central, and South America. Key limes actually come from Southeast Asia, and then they were introduced to the Florida Keys, Central and South America.
Key limes are harvested green and are yellow when ripe. They have a floral, aromatic, and sour taste.
Key limes have not been grown commercially in the US since the 1926 Miami hurricane. They are generally imported from Central or South America. Many Key lime pies in Florida are made with bottled juice, imported fresh limes, or from privately grown lime trees.
What is the difference between key limes and regular/Persian limes?
Key limes are smaller, have floral and more aromatic flavor, and are more sour. You can substitute about 1 Persian lime for about 3-4 Key limes.
Making key lime pie at home is so quick and easy. If you haven’t made it before – you’re in for a treat and I can assure you, you will be surprised by how easy it is. You need just 3 ingredients for the filling and 4 ingredients for the crust.
You could buy a premade graham cracker crust but I highly recommend making your own. A homemade crust tastes so much better than the store-bought and it’s ridiculously easy to make.
To make the graham cracker crust you will need:
1) Graham crackers – you can buy whole graham crackers and process them in a food processor to crumbs or purchase graham cracker crumbs. If there are no graham crackers where you live you can use any other crumbly cookies like digestive cookies, butter cookies, or petit beurre. I’ve also read some people use gingersnaps or crushed pretzels for this crust. You could also make cookie crust with nuts or shredded coconut – we’ve eaten in Bonefish Grill key lime pie with toasted pecans crust and it was super good but I must admit I prefer the plain graham cracker crust better. You just can beat the classic!
2) Brown sugar – you can use also white granulated sugar but it tastes a little bit better with brown sugar.
3) Butter – holds the crumbs together.
4) Salt – to balance the sweetness.
Pastry crust vs Graham cracker crust?
Some sources say that the Key lime pie used to be made with pastry crust rather than graham cracker crust before graham crackers became available in Key West. Graham cracker crust is also so much easier and quicker to make than pastry crust, so after opening the Overseas Highway that connects Miami with Key West and influx of tourists, people slowly shifted to making graham cracker crust instead of pastry crust. I love graham cracker crust so much in this recipe that I really can’t imagine making it with pastry crust but if you would like to give it a try you could use this recipe for pastry crust (this article also talks about why the pastry crust was used before the graham cracker crust).
To make the key lime pie filling you will need:
1) Key lime juice – I used Joe and Nellie’s bottled key lime juice (you can buy it on Amazon), I can’t even dream of finding fresh Key limes where I live. Using bottled juice is totally fine, I’m sure many Key lime pies in Key West are made with bottled juice. If you can find fresh Key limes, sure, use them. There is nothing better than using fresh. Juicing small Key limes can be a bit time-consuming though. You will need to juice about 30-40 small Key limes to get about 1 cup of juice! You can also use regular, Persian limes, your pie will also be delicious! The difference in flavor is small but noticeable. You will need about 6-8 Persian limes depending on how juicy and big they are. If you have fresh limes, you could also add some lime zest to your pie but I haven’t really seen that in the pies we ate.
When using Key limes: make sure they are yellow or green-yellow instead of dark green which indicates that they are ripe. Unripe fruit will be more sour.
TIP: An easy way to juice Key limes: I’ve read somewhere that you can cut Key limes in half or into quarters and put them into a garlic press to squeeze out the juice more quickly.
The recipe calls for an unusual amount of Key lime juice: 1 cup minus 2 tablespoons. The filling with 1 whole cup of juice was a little bit too tart for us, so I reduced the amount, and this was perfect. You can add as much juice as you want if you want it more tart.
2) Sweetened condensed milk – can not be substituted in any way.
3) Egg yolks – I like my Key lime pie with a minimal amount of egg yolks. Some recipes call for even 10 egg yolks! It’s a matter of taste! For me, the filling with lots of egg yolks tastes too eggy and it’s more thick. If you use a small amount of egg yolks, it really lets the citrus flavor shine. You can add as many egg yolks as you want, though, especially if you have some leftover (you may need to adjust the amount of lime juice). You can also add less and even none and make frozen key lime pie (you need to freeze it in order for it to be thick and not runny).
You can use leftover egg whites to make chocolate-dipped coconut macaroons.
For the whipped cream topping you can use heavy cream or heavy whipping cream.
The best Key lime pie recipe
The best Key lime pie – probably doesn’t exist! Just as everything – it’s a matter of taste. There are countless variations of this sweet citrus pie. There is even a cookbook called The Key West Key Lime Pie Cookbook by David Sloan. When he was researching his book, he has found there are at least 150,000 different ways to make it.
Some people like it tangier (simply add more lime juice), some like it less sweet (add less condensed milk), some like more or less cookie crust, some like it more creamy (add cream cheese or sour cream), some like it more eggy and rich (add more egg yolks, you can add as many as you like, some recipes call for 10 egg yolks!), some like it topped with whipped cream and some with meringue.
This is such a simple recipe you can easily adapt it to your taste. If you are not afraid of raw eggs you can just taste the filling and adjust its sweetness and sourness, or you can cook a small amount of the filling in a pot. It will curdle but you will be still able to assess its taste.
You will need a 9-inch (23 cm) deep dish pie pan for this recipe. If you don’t have a deep dish pie plate you can use half of the ingredients and bake it in a smaller 9-inch pie plate (so for the filling you will need: about 1/2 cup of lime juice, 1 can condensed milk, 2 egg yolks, and for the crust: 1 1/2 cups crumbs, 5 Tbsp butter, 3 Tbsp sugar).
You can also bake this pie as bars, using a 8-inch (20 cm) square pan (brownie pan). Baking time stays the same. You don’t have to make the rims for the crust, press the crumbs only into the bottom of the pan. I also recommend my recipe for Key lime pie bars! They are a little less tart and have cream cheese added to the filling to make it more creamy.
How to make it step by step
STEP 1: Start with making the crust: process the graham crackers and sugar in food processor until crumbs form.
STEP 2: Add the crumbs, sugar, salt, and melted butter into a 9-inch (23 cm) a deep dish pie pan.
STEP 3: Stir with a spoon until the crumbs are coated in butter.
STEP 4: Press the crumbs into the bottom and sides of a pan, forming a 2-inch (5 cm) rim. I like to use my hands or a spoon at the beginning and then I press the crumbs with a bottom of a measuring cup. Don’t worry if the rim is a little bit crumbly at this point.
STEP 5: Bake the crust for 10-12 minutes at 350°F (180°C). It should be firm and golden. Cool the crust slightly before filling it with the custard (10 minutes is enough). You can also fill it and bake right away but the filling will cook more evenly if the crust is cooled.
STEP 6: Make the filling: Using an electric mixer, whisk the egg yolks with condensed milk.
STEP 7: Slowly add the lime juice while mixing. Mix the filling for about 2 minutes.
STEP 8: You will see that the filling already starts to thicken – this is a chemical reaction between the egg yolks, sweetened condensed milk, and lime juice. Lime juice ‘cooks’ the egg yolks a little bit and the filling can thicken on its own. Baking is only needed to achieve a thicker consistency of the filling and to pasteurize the egg yolks.
STEP 9: Pour the filling into the baked crust.
STEP 10: Bake the pie for 20 minutes. It will be a little jiggly in the middle when you move with the pan. The top of the pie shouldn’t look wet but don’t try to touch it – it will leave marks.
Now comes the hardest part – waiting for the pie to set! You can’t really speed up this process. You could try to serve it after about 3-4 hours but it will be too hard to take clean nice slices out of the pan. I really recommend waiting at least 8 hours and preferably overnight to let the pie fully set – the crust and filling will have a perfect texture. First, let the pie cool to room temperature then put it in the fridge. You can cover your pie with a piece of plastic foil but be careful – it shouldn’t touch the surface of the pie – it will leave marks (that you can always cover with whipped cream!).
Now make your whipped cream by simply beating heavy whipping cream (or heavy cream) with sugar until stiff. Decorate the pie – you can just simply dollop the whipped cream on top of the pie or transfer the whipped cream into a piping bag fitted with a star tip and pipe nice swirls.
How to serve it: it tastes best chilled but not straight from the fridge. Its texture is a little bit too firm when completely cold. Leave it on the counter for 10-15 minutes to soften, then enjoy!
How to store it: This pie keeps very well. It’s best on the day of baking only because the crust is still a bit crunchy (it softens the next day). The filling is like freshly baked for at least 5 days. Keep the pie covered in the fridge. The whipped cream is best freshly prepared but it will also be okay-ish the next day.
Storing the crust: You can prepare the graham cracker crust 1-2 days in advance, cool it completely, then cover it tightly and store it in the fridge for up to 2-3 days.
How to freeze it: This pie freezes very well. It’s best to cut it into servings, wrap it in plastic foil and freeze for up to 3 months. Let thaw in the fridge overnight.
- Like I said before, my one and only acceptable topping is whipped cream.
- Some say that meringue topping is more authentic but from all the pies that we ate in Florida, only one was topped with meringue and we liked it with whipped cream so much more. If you’d like to give it a try though, follow the instructions for this apple tart with meringue topping. This recipe calls for 4 egg whites which is what you’ll have left from this pie recipe.
- You can spike your whipped cream with coconut rum or Kahlua.
Best Key Lime Pie in Florida Keys
It’s hard to pick the best Key Lime Pie that we ate in Key West and the Florida Keys. There were so many amazing pies!
- In the first photo, you see Key Lime Pie from Kermit’s. It’s one of the oldest shops selling Key lime pie in Key West. I remember it as one of the best pies, although I wasn’t a fan of the crust, it tasted a bit like store-bought crust. You can buy there many different flavors of Key lime pie, like strawberry, blueberry, or coconut key lime pie. There are also sauces and preserves with key lime juice. You can also buy bottled key lime juice to make this delicious pie at home. A huge hit for us was also Key lime pie on a stick which is basically frozen key lime pie (it’s made very similarly, but without the egg yolks) coated in chocolate, on a stick – it was absolutely amazing, I would choose this over regular ice cream any day!
- In the second photo, there’s Frozen Key Lime Pie we ate in Lorelei’s restaurant in Islamorada. It’s called “Lorelei’s World Famous “Frozen” Key Lime Pie Staff Favorite” which is not surprising considering that was one of our two favorite pies that we ate, but it’s not technically Key lime pie. As written above, it’s made very similarly, but without the egg yolks and it’s obviously frozen instead of being baked (I asked the waitress). It was served with mango sauce and it was just heavenly! If you are visiting Islamorada, this is something you just MUST try!
- The third pie is a Key lime pie topped with meringue that we ate in Midway Cafe & Coffee Bar in Islamorada. We weren’t fans of this pie since it came with a meringue topping. I think the one and only topping for Key lime pie is whipped cream! It was just too much with meringue in my opinion. We loved a sign in the cafe that has said “unattended children will be given espresso and a free kitten” – I would NOT like to see that, LOL.
- This is the pie we ate in Rams Head Southernmost in Key West along with these amazing chorizo breakfast tacos. As already mentioned before, we preferred pies with fewer egg yolks (the paler the better). This one was is very yellow so I assume a lot of egg yolks were added. It was good (we haven’t met a Key lime pie we didn’t like) but it was just not one of our favorites.
- This was one of the two favorite pies for us – we ate this pie in Key West Key Lime Pie Co. You can see in the photo how creamy it was! The texture was superb. It’s also very pale so I assume there are very little egg yolks added. It was very tart and the lime flavor was really shining through all this creaminess! My preference would be a just little less lime juice (although for my husband it was perfect), but it was really amazing.
We have eaten more pies while being in Florida but haven’t taken pictures of all of them (and now I regret that!)
Key Lime Pie variations
- Frozen Key Lime Pie – it’s seriously equally delicious – it’s made with just sweetened condensed milk and key lime juice, then it’s frozen.
- Key Lime Pie on a stick – it’s a slice of frozen key lime pie coated in chocolate and put on a stick – it’s so good!! it’s being sold by Kermit’s in the Florida Keys and also other parts of Florida.
- Key Lime Pie Bars – this is a very similar recipe to traditional Key lime pie, but it’s less tart (I added less Key lime juice) and I added a small amount of cream cheese to the filling – it’s more creamy, simply wonderful – we like it just as much as traditional Key lime pie.
- Key Lime Pie Martini – we drank it in Islamorada Brewery & Distillery. I can’t really develop the recipe now because I’m nursing but when I’m done (soon) it’s high on my to-do list! I took a picture of the ingredients on the menu, though, it says it’s made with: Islamorada vodka or Gin, fresh Key lime juice, pineapple juice, cream of coconut, vanilla syrup, and heavy cream. It seriously tastes like Key lime pie in form of a cocktail – simply amazing. They also produce beers – it’s a must try if you are in this region! I liked the orange-flavored beer “island citrus ale” best and my husband liked the coconut-flavored beer “coconut Key lime ale”.
Did you make this recipe? RATE THE RECIPE or tell me in the COMMENTS how you liked it! You can also add a photo of your dish. It would make me very happy and will help other readers. Thank you!!
The BEST Key Lime Pie Recipe
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graham cracker crust:
- 1 3/4 cups (175g) graham cracker crumbs 12 whole crackers
- 7 tablespoons (100g) unsalted butter
- 1/4 cup (50g) light brown sugar
- big pinch of salt
key lime filling:
- 4 egg yolks
- 2 (14-ounce/400ml) cans sweetened condensed milk 2 cans = 28 oz
- 1 cup – 2 Tbsp Key lime juice 210g, I used bottled ‘Joe and Nellie’s’ Key lime juice
- 1 cup heavy whipping cream or heavy cream
- 1 tablespoon powdered sugar
Make the graham crakcer crust:
- Preheat the oven to 350°F / 180°C / Gas Mark 4, no fan (if you have a convection oven reduce the temperature by about 20° or follow the manufacturer's instructions).
- If you’ve purchased whole graham crackers and not graham cracker crumbs, you need to pulse them in a food processor with sugar until fine crumbs form.
- Add the cookie crumbs, sugar, salt, and melted butter into a 9-inch (23 cm) deep dish pie pan. Stir with a spoon until all the crumbs are coated in butter.
- Press the mixture firmly into the bottom and up the sides of the pan, making a 2-inch (5 cm) rim. I like to start with a spoon and then press the crumbs with the bottom of a measuring cup.
- Bake the crust for 10-12 minutes or until golden.
- Chill the crust for 10 minutes before filling.
Make the key lime filling:
- In a large bowl, combine the egg yolks and sweetened condensed milk, mixing well with an electric mixer. Slowly add lime juice, while continuing to mix until well blended. Mix it for about 2 minutes.
- Pour the mixture into the baked pie shell and bake for 20 minutes. Take the pie out of the oven. It will be a little bit jiggly in the center but it should look set on the surface and not 'wet'. There's no need to test it with a cake tester – it will be still a little bit too wet, it needs to be chilled to fully set.
- Leave to cool to room temperature then refrigerate for 8 hours/overnight or until completely set and chilled. You can cover the pie with plastic foil but make sure it won't touch the surface of the pie.
- Beat heavy whipping cream with sugar until stiff. Serve the pie with whipped cream.
- The recipe calls for an unusual amount of Key lime juice: 1 cup minus 2 tablespoons. The filling with 1 whole cup of juice was a little bit too tart for us, so I reduced the amount, and this was perfect. You can add as much juice as you want if you want it more tart.
- Instead of graham crackers, you can use other crumbly cookies like gingersnaps. I used honey graham crackers for this recipe. You could also swap about 1/2 cup of cookie crumbs for ground nuts or shredded coconut.
- You can use fresh or bottled Key lime juice or freshly squeezed Persian lime juice (regular limes).
- For 1 cup of lime juice you will need about 30-40 Key limes or 6-8 regular limes, depending on how big and juicy they are.
- How to serve it: it tastes best chilled but not straight from the fridge. Its texture is a little bit too firm when completely cold. Leave it on the counter for 10-15 minutes to soften, then enjoy!
- How to store it: This pie keeps very well. It’s best on the day of baking only because the crust is still a bit crunchy (it softens the next day). The filling is like freshly baked for at least 5 days. Keep the pie covered in the fridge. The whipped cream is best freshly prepared but it will also be ok-ish the next day.
- If you’d like less crust, use these amounts: 1 1/2 cups crumbs, 5 Tbsp butter, 3 Tbsp sugar.
- How to freeze it: This pie freezes very well. It’s best to cut it into servings, wrap in plastic foil and freeze for up to 3 months. Let thaw in the fridge overnight.
- Storing the crust: You can prepare the graham cracker crust 1-2 days in advance, cool completely, then cover it tightly and store in the fridge for up to 2-3 days.
- Chilling the pie: You can’t really speed up to process. You could try to serve it after about 3-4 hours but it will be too hard to take clean nice slices out of the pan. I really recommend waiting at least 8 hours and preferably overnight to let the pie fully set – the crust and filling will have a perfect texture. First, let the pie cool to room temperature then put it in the fridge.
- You will need a 9-inch (23 cm) deep dish pie pan for this recipe. If you don’t have a deep dish pie plate you can use half of the ingredients and bake it in a smaller 9-inch pie plate (so for the filling you will need: about 1/2 cup of lime juice, 1 can condensed milk, 2 egg yolks, and for the crust: 1 1/2 cups crumbs, 5 Tbsp butter, 3 Tbsp sugar).
- You can also bake this pie as bars, using a 8-inch (20 cm) square pan (brownie pan). Baking time stays the same. You don’t have to make the rims for the crust, press the crumbs only into the bottom of the pan.
- Calories = 1 serving (1/12 of the recipe). This is only an estimate!