Heat the milk a little with 1 teaspoon of sugar and let the yeast dissolve.
Sift the flour, add the sugar, vanilla sugar, salt and lemon peel. Mix well.
Add the melted margarine and the beaten yolks, then add the milk with the dissolved yeast. (don't put all the milk in at once, you may not need everything)
Knead the dough until it becomes non-sticky and makes air bubbles.
Leave the dough with flour powder to rise until it doubles in volume in a warm place, away from electricity.
Remove the leavened dough on the work table lined with a little flour and spread it with the rolling pin until you get
the thickness of a finger. Using a glass, cut the donuts and let them rise for another 10 minutes.
Fry the donuts in plenty of oil until golden brown on both sides.
Leave on a paper towel until cool and powder with vanilla powdered sugar.