For the pineapple cake, drain pineapple slices and spread on the bottom of a springform pan. Cream butter, sugar, eggs and vanilla sugar.
Fold in flour with baking powder and stir in milk. Pour the batter onto the pineapple slices and bake at 175°C in a preheated oven for about 60 minutes. Turn out the pineapple cake and sprinkle with powdered sugar.