Knead the flour, baking powder, 150 grams of sugar, vanilla sugar and melted butter into crumble. Put 2/3 of the crumble in a greased springform pan sprinkled with breadcrumbs and press down as a base. Mix the brittle with the remaining crumble.
Peel the apples, remove the core, cut into thin slices and drizzle with lemon juice. Add the lemon zest, the cream and 50 grams of sugar. Spread on the base and sprinkle with the brittle crumble.
Bake at 200 ° C for 40 to 50 minutes, cover with foil, 10 minutes before the end. Let cool down well.