Melt 175 g butter and let it cool down a little. Roughly chop the chocolate. Mix flour, baking powder, brown sugar, 1 packet of vanillin sugar, salt and cocoa in a bowl. Place 5 eggs in a mixing bowl and whisk until creamy
Let melted butter run in and stir in. Add flour-sugar mixture in 2 portions and stir in. Stir in crème fraîche, then fold in chocolate. Pour the dough into a greased, floured fat pan of the oven (35 x 40 cm). Put aside
For the quark mixture, whisk 125 g butter, sugar and 1 packet of vanilla sugar with the whisks of the hand mixer until creamy. Stir in 7 eggs individually. Stir in semolina. Stir in 3 portions of quark
Spread the curd mixture evenly over the dough with a large tablespoon. Pull through with a fork (marble). Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 55-60 minutes on the middle shelf. Then remove from the oven, place on a cake rack and allow to cool
Dust with icing sugar as desired. Cut into pieces. Serve with whipped cream