Beat butter and white sugar together in a bowl using an electric mixer until smooth and creamy. Add egg yolks to creamed butter mixture and beat until smooth. Mix flour and almonds together in a separate bowl; slowly stir into creamed butter mixture, kneading the dough toward the end until smooth. Place dough in an airtight container and refrigerate until chilled, at least 1 hour.
Preheat oven to 325 degrees F (165 degrees C).
Roll small pieces of dough into balls. Carefully roll each ball into a 2 1/2-inch rope; form into a crescent shape and place on a baking sheet. Repeat with remaining dough.
Bake in the preheated oven until cookies are golden brown, about 15 minutes. Cool cookies on baking sheet for 3 minutes.
Spread vanilla sugar into a shallow dish or pie plate. Lift cookies from baking sheet using a spatula and turn them, top-side down, into the vanilla sugar. Cool cookies completely on a wire rack.