Mix the flour, except for one tablespoon, with the baking powder and sugar. Melt the butter, pour it into the flour and use the dough hooks to make crumbles. Grease a springform pan (24 cm diameter). ¾ Spread the crumbles on the bottom of the pan and press down a little, forming an approx. 2 cm high edge. Cover and chill for about 30 minutes.
In the meantime, wash the plums, stone them and cut them into wedges.
For the filling, stir the softened butter with the sugar until frothy. Mix in the eggs one by one. Also stir in the quark, pudding powder and lemon juice. Spread the filling on the dough base and spread the plums on top. Mix the remaining crumble with the tablespoon of flour and spread around the outer edge. Bake in the oven at 200 ° C, fan oven 180 ° C, gas mark 3 for about 50 minutes.