Grease the fat pan (approx. 32 x 39 cm; approx. 3.5 cm deep). Cream fat, sugar, salt and lemon peel. Stir in egg. Mix flour and baking powder, stir in half of it. Knead the rest first with the dough hooks of the hand mixer, then briefly with your hands to form crumbles.
Spread 2/3 of the crumble as a base on the fat pan, press it on. Spread jam, plum and applesauce in large blobs on top. Sprinkle the rest of the crumble and decorating sugar on top. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/gas: level 2) for 45-60 minutes. Let them cool down. Serve with ice cream