Beat the room-temperature butter with the sugar, salt and vanillin using a mixer.

Add the sour cream and egg, mix again.

Sift in the flour with the baking powder in portions and knead the dough.

On a flour-dusted counter, roll out the dough to a thickness of 0.5-0.7 cm. Run a fork over it for the pattern, cut out the cookies with a cutter, and place on a baking sheet.

Brush the cookies with beaten egg yolk and bake for 25-30 minutes in an oven preheated to 180 C.

Let the finished cookies cool. Enjoy!