Melt 240 g fat. Mix 350 g flour, 1 tablespoon cocoa and 120 g sugar. Pour fat on top and knead everything into crumbles. Let it cool down. In the meantime peel and halve apples and cut out the core.
Drizzle apple halves with lemon juice. Cream 200 g fat, 200 g sugar and vanillin sugar. Stir in eggs one after the other. Mix 200 g flour, baking powder, 1 tablespoon cinnamon and 1 tablespoon cocoa.
Stir in the flour mixture by the spoonful. Fill the dough into a greased springform pan (26 cm Ø), dust with flour and smooth it down. Place apple halves evenly on top. Spread crumbles evenly on the apples.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level: 3) for about 1 hour. Cover the cake if necessary after 40 minutes baking time. Remove the cake from the oven and let it cool down on a cake rack.
Remove the cake from the edge and dust with 1 tablespoon cinnamon and icing sugar.