Add 150 ml of milk to the bowl. Heat the milk slightly, add sugar (50 gr.), add 5 gr. granulated yeast, add a couple of spoons of flour. Stir the mixture and put it in a warm place to dissolve the yeast. After a certain time, a cap of small bubbles forms on the surface. The dough is ready. Next, add the egg (1 PC.), add 1 pinch of salt, add 1 tablespoon of sour cream and 1 teaspoon of vanilla sugar. Beat the mixture with a whisk.