Sift flour into a large bowl. Add yeast to warm milk. Mix. Cover with a towel and put in a warm place for 20 minutes. After 20 minutes, add sugar, salt, yolks to yeast and milk. Beat.
Add warm butter. Mix thoroughly. Pour the mixture into flour. Knead elastic dough. Cover the dough with a towel and put in a warm place for 40 minutes. The dough should rise.
Sprinkle the table with flour, roll out dough 1 cm thick, cut out donuts. Allow them to lie down for another 20 minutes.
Heat the oil. Fry donuts on both sides until golden brown. There should be enough frying oil to half the donut. Spread our yeast donuts before serving on a paper towel to remove excess oil. Sprinkle with powdered sugar.