Drain the pineapple. Put 4 slices aside for garnishing, cut the rest into pieces. Beat the fat, sugar and vanilla sugar until fluffy. Stir in eggs bit by bit. Mix flour, baking powder, salt and cocoa and stir in by the spoonful.
Add rum and milk. Carefully fold in the pineapple pieces. Pour the dough into a greased pan (1 1/2 litre capacity) and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for approx. 1 1/4 hours.
Take out and let it cool down well. Whip the cream until stiff and spread it on the cake. Sprinkle with coconut flakes all around. Halve the remaining pineapple slices and place them on the cake. Decorate with mint leaves and lime flakes.
Results in about 15 pieces.