For the banana slices, cream the margarine until fluffy. Add the powdered sugar and eggs and mix again until fluffy. Mix flour, baking powder and cocoa and stir in. Spread the dough on a greased floured baking tray and bake in a preheated oven at 180 °C.
Cut the bananas in half lengthwise. Cover the cooled dough with the halved bananas.
For the cream, mix the milk, cornflour and egg yolks in cold water and bring to the boil, stirring constantly. Stir in the sugar and allow to cool. Then add by the tablespoon to the butter, stirring until fluffy. Season to taste with rum and lemon juice. Spread the cream over the bananas.
For the chocolate glaze, melt the chocolate and butter in a bain-marie and stir until smooth. Glaze the banana slices with it.
Preparation Tip:
You can cover some banana slices with chocolate and decorate the banana cake with them.