Mix flour and icing sugar. Add butter in pieces and 1 egg. Knead everything first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Grease the fat pan of the oven and dust it with flour. Pour in the dough and press it with your hands to a flat bottom, pulling up the edges. Sprinkle the base with breadcrumbs.
Place in a cool place. Mix curd, mascarpone, 200 g sugar, vanillin sugar and lemon juice until smooth. Stir in 8 eggs one at a time, then stir in the pudding powder at the end. Halve the mixture. Sift cocoa over one half and fold in. Pour light-coloured mixture into the mould first. Spread the dark mixture in patches and fold in with a spoon in a streaky mixture. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) on the lower rack for 50-60 minutes. Leave to cool for approx. 15 minutes with the oven door open. Take out and let cool down. Caramelise 100 g sugar and 3-4 tbsp water in a coated pan until golden. In the meantime lightly coat aluminium foil with oil.
Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) on the lower rack for 50-60 minutes. Leave to cool for approx. 15 minutes with the oven door open. Take out and let cool down. Caramelise 100 g sugar and 3-4 tbsp water in a coated pan until golden. In the meantime lightly coat aluminium foil with oil. Add the hazelnuts to the caramel and cover with it. Place spoonfuls of hazelnuts in small heaps on the foil and let them cool down. Cut the cake into pieces and decorate with hazelnut caramel
Waiting time 1 hour