Beat the butter with the sifted sugar, vanilla sugar, salt, lemon juice and zest, vanilla flavor and rum until frothy. Gradually stir in the egg yolks. Mix the flour and baking powder and add sifted alternately with the cream to the yolk mixture. Beat egg whites into snow and fold into the batter. Finally stir in the mashed bananas and coconut flakes into the batter.
Pour the dough into a greased, floured Gugelhupf pan and bake in the preheated oven at 175 ° C for about 50 - 60 minutes.
Let the Gugelhupf cool down and turn it over, cover with strips of chocolate glaze and decorate with coconut flakes.