Mix the quark with the sugar and vanilla sugar, milk, oil and salt. Mix and stir in the flour and baking powder, then knead everything into a smooth dough. Mix the ground hazelnuts with the sugar, then add ½ egg yolk, egg white, water and bitter almond oil and stir into a smooth mixture. Roll out the dough into as long a rectangle as possible. This works best on a floured tea towel. Then spread the nut mixture on top and roll up the dough. Shape the roll into a wreath on a baking sheet lined with baking paper, pressing the ends together well. Cut the wreath diagonally a couple of times with a sharp knife. Mix the remaining egg yolks with 1 tablespoon of milk and coat the wreath with it. Bake at 175 ° C for approx. 50 minutes.