Mix 500 g flour, almonds, baking powder, sugar, lemon peel and 1 pinch of salt. Add butter in flakes and eggs. Mix everything first with the dough hooks of the hand mixer and then briefly with your hands to make crumbles.
Chill 1/3 crumble for about 30 minutes.
Grease the baking tray (approx. 35 x 40 cm). Spread the rest of the crumbles on it and press it on as a cake base. Spread plum puree on top.
Loosely mix cold crumbles and 2-3 tablespoons of flour and sprinkle onto the plum puree, rubbing or crushing it between your fingers.
Bake the cake in the preheated oven (electric oven: 200°C/circulating air: 175°C/gas: level 3) for 25-30 minutes. Let them cool down.