For the dough, mix flour, except for one tablespoon, and sugar. Melt the fat and pour over it. Knead the ingredients into crumbles using the hand mixer. Spread 3/4 of the crumbles on the bottom of a greased springform pan (24 cm Ø).
Press down two centimetres at the edge. Cold place. In the meantime, wash plums for the filling and cut them into slices from the stone. Stir the fat until frothy. Add sugar and eggs and stir until creamy.
Stir in the quark, pudding powder and lemon juice. Pour the quark cream onto the dough. Spread plums on top. Shake remaining crumbles and flour and spread on the edge of the springform pan. Bake in the preheated oven (electric: 200°C/ gas: level 3) for 50 minutes.
Allow to cool slightly, remove from the mould and dust with icing sugar before serving.