Grind the cottage cheese through a sieve. Add sugar, vanilla and a pinch of salt. Mix it.
Add kefir and soda, mix.
Add flour. Knead a soft, elastic dough.
Cut the apple in half. Peel the apple if desired. Remove the core. Cut into thin slices.
Roll out the dough into a layer 2-3 mm thick.
With a small cup suitable for coffee (7 mm in diameter), cut out circles from the dough.
Put a slice of apple on half a circle of dough. If necessary, sprinkle a little sugar and cinnamon to taste (I mixed 3 tsp sugar and 0.5 tsp cinnamon, I got a sweet and sour apple).
Cover with the second half of the dough cup, covering the apple.
Place the cookies on a baking sheet lined with parchment and bake in a preheated 180 degree oven for about 15-20 minutes until browned.