For the crumbles, mix flour, fat, sugar and cinnamon into crumbles using the dough hooks of the hand mixer. Grease a deep baking tray (35x40 cm) well. Put 2/3 of the dough on the bottom and press it down.
For the filling, drain the apricots well, then spread them on the base. Stir the fat until frothy. Add sugar, vanillin sugar and lemon peel and mix. Stir in the eggs bit by bit.
Place the quark, yoghurt and custard powder on the egg cream and stir in. Smooth on the apricots. Spread the remaining dough as crumbles on the quark cream. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for approx. 50 minutes.
Let the cake cool down and dust with icing sugar shortly before serving. Makes about 20 pieces.