Cut the chocolate into small pieces. Mix 200 g butter, 125 g sugar, 250 g flour and almonds into crumbles using the dough hooks of the hand mixer. Stir in 100 g chocolate and chill. Carefully wash, clean and drain the currants. Cream 250 g butter, 150 g sugar, vanillin sugar and salt. Stir in the eggs one by one. Mix 375 g flour and baking powder.
Alternate briefly with sour cream. Stir in the remaining chocolate. Spread the dough on the greased fat pan of the oven. Spread the berries on top. Cover with crumbles. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 30 minutes. Let cool, cut into pieces and serve fresh