Mix the butter with the sifted sugar, vanilla sugar, rum, vanilla flavor, salt and egg yolk until frothy. Then mix in the curd. Stir in flour sifted with baking powder alternately with milk. Beat the egg whites into firm snow and carefully fold into the mixture with the raisins.
Pour the dough into a greased, floured Gugelhupf tin and bake at 180 ° C for about 60 minutes.
Let the Gugelhupf cool, turn it out and sprinkle with icing sugar.