Dissolve the yeast in the warm milk, add 2 tbsp sugar and 4-5 tbsp flour. Beat the eggs with the remaining sugar, add the butter, vanillas, activated yeast, flour with salt and knead a soft, nonstick dough. Leave it to rise until doubled in volume.
Roll out the dough into a sheet about 1/2″ (1 cm) thick. Cut out circles using a glass. Cover them and let rise for another 20 min. Then turn on the other side and let them rise a bit more. Fry in heated oil on moderate heat. Take them out onto paper towels.
Cream: Put half the milk to come to a boil, beat the other half with the eggs, sugar, flour and vanillas. In a thin trickle, while stirring nonstop, pour the mixture into the boiling milk until the cream thickens.
Fill the donuts using a pastry bag with an elongated tip. Sprinkle the ready donuts with powdered sugar.