Peel and quarter the apples and cut out the core. Cut the apple quarters lengthwise and sprinkle with lemon juice. Separate the eggs. Mix fat, egg yolk and sugar until creamy.
Stir lemon zest, quark, milk, semolina and flour into the egg mixture. Beat the egg whites until stiff, letting the vanilla sugar trickle in. Fold the beaten egg white into the quark mixture. Pour into a greased casserole dish (approx. 30-32 cm Ø) sprinkled with breadcrumbs.
Add the apple quarters and sprinkle with almond flakes. Bake in the preheated oven (electric oven: 175 °C/ gas: level 3) for approx. 45 minutes. Heat up the apricot jam and brush the apples with it 10 minutes before the end of the baking time.
Sprinkle with brown sugar and icing sugar as desired.