As in one of my recipes, we prepare sourdough dough. To do this, add 2 tablespoons of sugar, 1 tablespoon of flour and 10 grams of dry fast-acting yeast to the warm milk. Stir and leave in a warm place for 20-30 minutes. As the yeast started working and the sourdough rose, add 1 egg, 70 g of melted butter and flour. Knead the dough. Remove to a warm place. For an hour.