Beat the butter with the sifted sugar, vanilla sugar and rum until frothy. Stir in egg yolks one at a time. Mix flour with baking powder, sieve and mix with chocolate cubes and the chopped pumpkin seeds. Stir everything into the yolk mixture. Beat the egg whites into the snow and fold into the dough with the grated apples.
Grease and flour the Gugelhupfform, fill in the dough and bake in the preheated oven at 175 ° C for about 60 minutes.
Let the Gugelhupf cool, turn it out and decorate with icing sugar, pumpkin seeds and halved walnuts.