Cut the butter into very small cubes. Add it to a mixing bowl along with the flour, sour cream, powdered sugar, salt, vanilla, cardamom, and almond extract.
1 stick + 3 tablespoons (155g) cold butter, 2 cups (250g) flour, ½ cup (115g) sour cream, ½ cup (60g) powdered sugar, big pinch of salt, 1 teaspoon pure vanilla extract, 1/8 teaspoon cardamom, a couple of drops almond extract
Knead by hand or mix with a stand mixer fitted with a paddle attachment until a dough forms.
Flatten the dough, wrap it in plastic wrap, and refrigerate for 1 hour.
Preheat the oven to 350°F (180°C).
Roll out the dough on a counter or rolling mat lightly dusted with a mixture of flour and powdered sugar. Cut out rounds about 3 inches (7.5 cm) in diameter, then cut out smaller rounds in the center, about 1 inch (2.5 cm).
Place the cookies on a baking sheet lined with parchment paper, leaving a little space between them.
Make the egg wash: in a small bowl, whisk the egg with a little water.
Brush the cookies with the egg wash, then sprinkle with pearl sugar or granulated sugar (but you’ll lose a lot of the amazing crunch if you skip the pearl sugar).
Bake until lightly golden on top, about 15–17 minutes.
Let cool briefly on the baking sheet until easy to handle, then transfer to a wire rack to cool completely.
Enjoy!