Melt 150 g butter and let it cool down a little. Mix flour, 150 g sugar and vanillin sugar in a bowl. Add butter and knead into crumbles with your hands. Put about 2/3 of the crumbles into a greased springform pan (26 cm Ø) and press them to a flat bottom. Pre-bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes
Wash the currants, drain well and remove from the panicles. Mix the starch with 50 ml juice until smooth. Bring 200 ml juice and 3 tbsp. sugar to the boil, remove from heat. Stir in the starch. Bring to the boil while stirring and simmer for about 1 minute. Mix in about 3/4 of the currants and let it cool down a bit. Put compote on the pre-baked cake and smooth it down. Let cool off
For the quark mixture, mix 125 g fat with 125 g sugar until foamy. Stir in lemon juice and eggs one after the other. Also stir in the quark and pudding powder. Carefully pour the quark mixture onto the compote and smooth it down. Mix remaining currants and crumbles and sprinkle on the quark mixture. Bake in the oven at the same temperature for about 50 minutes. Cover if necessary during the last 10 minutes. Let it cool down on a cake rack. Dust with icing sugar and serve decorated with currants. Whipped cream tastes good with it