Beat the fat, sugar and vanilla sugar with the whisk of the hand mixer until foamy. Gradually stir in the eggs. Add lemon juice and banana liqueur. Mix 200 g flour, cornstarch and baking powder and fold in by the spoonful.
Peel and slice the bananas. Turn in the remaining flour and add 60 g of grated coconut to the dough. Fill into a greased box form (2 litres capacity), smooth it down and bake in a preheated oven (electric cooker: 200 °C/ gas: level 3) for about 1 hour.
If necessary, cover the cake with parchment paper after 40 minutes baking time. Let the cake cool down in the tin. In the meantime melt the chocolate coating in a water bath. Remove the cake from the mould and cover with couverture, allow to dry briefly.
Roast the remaining grated coconut in a pan without fat until golden brown. Leave to cool. Garnish banana cake with banana chips and grated coconut. Let the chocolate coating dry. Results in about 20 pieces.