Pour the sponge cake, egg yolks whipped with sugar into a bowl, add melted warm butter, pour in warm cream, alcohol – mix with a mixer, add sifted wheat flour, salt, vanilla sugar in portions, knead the dough with a hook or a bread maker attachment. Knead the dough for 10-15 minutes. With manual kneading, first knead with a spoon, then adding flour to proceed to manual kneading. The dough turns out sticky - if you knead it by hand, you can't do without a scraper! Sprinkle the dough with flour when kneading, so that it does not clog!