For the apple-chocolate muffins, separate the eggs and beat the egg whites until stiff. Beat butter, sugar, vanilla sugar and yolks until fluffy. Add the chocolate, apple and milk and mix well.
Mix the flour with the baking powder and fold into the mixture alternately with the snow. Place 12 paper muffin cups in the wells of the muffin tray and spread the mixture evenly in them.
Bake in the preheated oven at 160 °C for approx. 25 minutes.