For the crumbles, knead 100 g fat, 200 g flour, honey and 1 sachet of vanilla sugar into crumbles using the dough hooks of the hand mixer. Keep cold. For the dough, mix 175 g fat, 1 packet of vanillin sugar, salt and sugar with the whisks of the hand mixer until creamy. Stir in the eggs one by one. Mix 300 g flour, cocoa, baking powder and nuts. Peel bananas, sprinkle with lemon juice and mash with a fork.
Stir bananas and flour mixture into the fat-egg cream. Grease a box form (30 x 11 cm; 2 litres capacity) and sprinkle with breadcrumbs. Add the dough and smooth it down. Spread crumbles over it. Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 1/2 hours (test with sticks). Remove from the oven, let it rest on a cake rack for about 10 minutes, then turn out of the tin and let it cool down
1 hour waiting time