Roughly grate the marzipan. Put butter in flakes, marzipan, sugar, flour and egg in a bowl. First knead into crumbles with the dough hooks of the hand mixer, then with your hands. Grease a springform pan (26 cm Ø) and dust with flour. Put approx. 2/3 of the crumbles on the bottom and press it down. Sprinkle with breadcrumbs and chill for about 30 minutes
Wash blueberries, drain well, mix with jam. Spread on the floor. Add the rest of the crumbles. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) on the bottom shelf for 25-30 minutes. Remove and let cool on a cake rack. Remove from the tin and serve dusted with icing sugar. Whipped cream tastes good with it
Waiting time approx. 30 minutes