For the crumbles melt butter and let it cool down for about 5 minutes. Mix flour, sugar, vanilla sugar, 1 pinch of salt and lemon peel. Slowly knead the liquid butter with the dough hooks of the hand mixer. Cover and chill for approx. 30 minutes.
Peel, halve and core apples. Cut the apple halves several times lengthwise on the curved side or carve them deeply with a fork. Sprinkle with 3 tablespoons of lemon juice
Grease a grease pan (approx. 32 x 39 cm). Spread 2/3 of the crumbles as a base on the fat pan and press on. Place the apple halves on top with the curvature facing upwards. Spread the rest of the crumble over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 45-50 minutes. Let the cake cool down. Stir icing sugar and 1-2 tablespoons lemon juice until smooth. Spread the icing over the cake. Whipped cream tastes good with it
Waiting time approx. 1 hour