✅Ingredients:
kefir or sour cream, 200 g;
flour, 450 g;
baking powder, 1 tsp;
butter, 250 g;
egg, 1 piece;
vanillin.

✅Filling:
flour and sugar 250 g each;
butter, 100 g;
vanillin.

✅Cooking:
Sift the flour and mix with baking powder.
Grind the chilled butter into the flour on a coarse grater and grind the mixture into crumbs.
Add sour cream or kefir, egg and vanillin to the mixture.
We collect the mass into a ball of dough. The mass should be very pliable, smooth and homogeneous.
Cover the dough and place in the refrigerator for 20 minutes.
For the filling, sift the flour and mix with sugar.
Add the softened butter to the mass along with vanilla and grind the mass until smooth. Can be done with a spatula or your hands.
Sprinkle the table with flour, roll out a thin layer of dough and sprinkle it with crumb filling.
Roll up a tight roll, press it with a rolling pin and roll it out lightly.
Lubricate it with beaten yolk. Decorate with patterns and cut into triangles or simply portioned pieces.
Line a baking sheet with parchment and lay out the cookies.
Bake at 180 degrees until golden brown.

You will definitely like such a delicate pastry due to the melted butter inside.