Add oats, milk, water, sweetener, salt, and vanilla to a medium/large heavy-bottomed pot.
Bring to a boil then cook for 10 minutes, stirring frequently (to prevent burning at the bottom of the pot) until oats are soft and almost all the milk has been absorbed.
While the oatmeal is cooking, prepare the strawberries: wash them, dry them, and remove the tops. Mix about 1/3 of the strawberries in a blender until smooth, cut 1/3 of the strawberries into chunks, and slice the remaining 1/3 of the strawberries (to put on top of your oatmeal, alternatively, you could just chop all your strawberries).
When the oatmeal is done, add heavy cream or coconut oil, strawberry puree and chopped strawberries to the oatmeal, and stir to combine (I don´t bring this again to a boil to preserve the freshness of the strawberries, but I do bring it to a boil if I plan to serve it the next day). Your oatmeal will thicken as it cools.
Pour your oatmeal into bowls and top with the remaining sliced strawberries.
Enjoy!