Mix the flour with the baking powder in a bowl. Add 125 g sugar, 1 egg, lemon juice and 125 g cold, sliced butter and work with a whisk until crumble is formed. Put half of the crumble in a springform pan and press down on the whole area.
Mix the semolina, quark, 250 g sugar, 125 g butter, vanilla sugar, juice of the second lemon, a little lemon zest and 4 eggs together and spread the mixture on the bottom. Spread the rest of the crumble on the quark filling.
Bake in the gas stove at level 3-4 for about 45 minutes (should be 200 ° electric, 180 ° convection - no guarantee). The cake can be baked the day in advance so that it still has time to steep.