Melt the butter. Put 375 g flour, 200 g sugar, almonds, cinnamon and salt in a bowl and knead to make crumbles. Sift 25 g flour over it, shake everything again.
Peel and quarter the apples and drizzle with lemon juice. Separate the eggs. Mix the egg yolks, quark, 100 g sugar, lemon zest and pudding powder together. Beat the egg whites with 25 g sugar until stiff. Pull the egg whites into the cream.
Put 2/3 of the crumble in a greased springform pan (26 cm). Cover with apples and spread the curd mixture on top. Sprinkle with the remaining crumble.