Peel and quarter the apples and cut out the core. Cut apple quarters into slices and mix with lemon juice. Pour cream into a bowl. Wash and dry one cup of cream and measure 1 cup (approx. 230 g) of sugar.
Add the sugar, 1 packet of vanilla sugar and lemon zest to the cream and beat with the whisk of the hand mixer until half stiff. Stir in the eggs one by one. Mix 3 cups (approx. 450 g) of flour and baking powder and stir in briefly.
Spread the dough in a greased, flour-polluted fat pan (32 x 39 cm) and spread the apples on top. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 15 minutes.
In the meantime, melt butter for the crumbles at low heat. Mix 2 cups (approx. 300 g) flour, 3/4 cups (approx. 175 g) sugar, 1 packet vanillin sugar and salt in a bowl.
Add butter at once and knead with the dough hooks of the hand mixer to thick crumbles. Sprinkle with a tablespoon of flour and shake again. Sprinkle crumbles on the pre-baked apple pie and bake in 15-20 minutes.
Cut the cake lukewarm or cold into pieces and sprinkle with icing sugar as desired. Serve with whipped cream, whipped half stiff.