Roast the hazelnuts in a pan without fat, take them out and let them cool down. Mix 100 g flour, 50 g sugar, 75 g soft butter and hazelnuts with the dough hooks of the hand mixer to form crumbles and chill. Sort the berries, wash if necessary. Grate marzipan. Mix 250 g butter, 200 g sugar, marzipan and vanilla sugar with the whisk of the hand mixer until smooth and creamy.
Stir in the eggs one by one. Mix 400 g flour and baking powder and stir in alternately with the yoghurt. Spread the dough on a greased and floured baking tray (32 x 39 cm) and cover with berries. Finally, sprinkle with crumbles and bake in the middle of the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 35-45 minutes. Dust the cake with icing sugar
1 hour waiting time