Remove 1 tablespoon of the sugar and mix with the dry yeast and lukewarm water and let stand for 10 minutes.
Mix the flour with the remaining sugar, vanilla sugar and salt. Put the yeast porridge on top and knead well. Add the melted butter (never too hot), the lukewarm milk and the eggs and knead into a soft dough with the kneading dough. Roll out the dough as thick as a thumb. Use a large round cookie cutter to cut out round circles. Poke a small hole in the center of the circle. Let the donuts rest for an hour.
Let the oil get hot in a wok and fry the donuts there until light brown. If desired, decorate the donuts with icing or chocolate icing.