In a bowl, mix the eggs and yogurt, and the previously extinguished with vinegar soda. Stir well, add the sifted flour with the salt.
Knead a soft dough. Divide it into balls and shape them with fat or flour. Put the balls in a greased and floured pan. At the center of each, put on a small lump of cheese and butter, press it with your thumb inside and cover it with the dough.
Spread egg yolk on the soda buns and sprinkle them with sesame or poppy seeds. Bake until pink in a preheated 374°F (190 °C) oven.