Mix flour (except 2 tablespoons), hazelnuts, baking powder and 125 g sugar. Add 2 tablespoons of liqueur and butter in flakes. Use the dough hooks of the hand mixer to make crumbles.
Sprinkle the rest of the flour over it and shake everything. Line the bottom of a springform pan (26 cm Ø) with baking paper, fill in half of the sprinkles, press down slightly. Put the crumbles in a cool place for about 30 minutes.
Separate eggs. Cream 125 g sugar and egg yolk. Stir in quark, pudding powder and 3 tablespoons of liqueur. Beat the egg white with a pinch of salt until stiff, fold into the quark mixture. Sort the currants.
Pour the curd mixture onto the base and sprinkle with currants. Spread the rest of the crumbles on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 60 minutes.
Remove from the mould and let it cool down in the mould. Loosen the mould edge. Dust the currant panicles with icing sugar for decoration and place them on the cake.