Peel the cabbage, onion and cut them into thin strips. Peel and finely chop the garlic. Sift the flour together with the baking powder. Preheat oven to 200°C.
Prepare the base: mix the egg with kefir, then add the flour with baking powder and mix everything well with a mixer.
Prepare the filling: fry the onion in heated olive oil until golden brown. Add garlic and fry for another 2 minutes.
Add cabbage and fry for 5 minutes. Cover the pan with a lid and simmer the cabbage for 10 minutes over low heat. Then add salt and pepper.
Place the prepared filling on the bottom of the mold and fill with kefir mixture.
Place the mold in an oven preheated to 200°C for 15-20 minutes. Turn off the oven and leave the finished pie in it for 20 minutes.
Cut into portions and serve.