Melt the fat in a pot at low heat and let it cool down. Sift icing sugar. Cream eggs and vanilla sugar with the whisk of the hand mixer. Add icing sugar by the spoonful and stir until the mixture is thick and foamy. Add melted fat and Baileys slowly while stirring.
Mix flour, starch and baking powder, sieve over the egg mixture and stir in briefly until a smooth dough is formed. Grease a cake tin (approx. 2 litres capacity) and sprinkle with breadcrumbs. Pour in the dough and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 1/4 hours. Let the cake rest in the pan for approx. 15 minutes, turn out onto a cake rack and let it cool down. Dust with icing sugar and cocoa and serve
Waiting time approx. 15 minutes