First, grease a cake springform pan with a diameter of 26 cm.
Mix flour, sugar, vanilla sugar, nuts, butter in flakes to crumble.
Press the crumble into the pan as a base. Sprinkle with breadcrumbs.
Refrigerate the base and the rest of the crumble for about 20 minutes.
Peel, quarter and core the apples. Cut quarters in half and sprinkle with juice of one lemon.
Mix semolina, curd, mascarpone until creamy and fold in 1 hect. Fold in 1 tablespoon flour.
Dry apples and spread evenly on the crumble base.
Spread the curd mixture on top. Sprinkle the rest of the crumble on top, crumbling it by hand.
Bake in the preheated oven at 175 °C for about 15 minutes.
Allow to cool in the pan, then dust with powdered sugar.