Peel, quarter and core apples and dice them. Put them in a pot with 150 ml apple juice and 1 sachet vanilla sugar, bring to the boil, cover and cook for about 5 minutes. Stir 1 tbsp. starch with 50 ml apple juice until smooth.
Pull the pot off the stove. Stir in the starch. Let simmer for about 1 minute while stirring. Let it cool down, stirring again and again.
Wash, halve and stone the plums. Put them in a pot with 150 ml apple juice, cinnamon stick and 1 tbsp sugar, bring to the boil. Cover and cook for about 5 minutes. Stir 1 tbsp. starch with 50 ml apple juice until smooth.
Pull the pot off the stove. Stir in the starch. Let simmer for about 1 minute while stirring. Let it cool down, stirring again and again, remove the cinnamon stick.
For the crumbles, put flour, butter in flakes, 200 g sugar, salt, 1 packet of vanillin sugar and egg in a large mixing bowl. First use the dough hooks of the hand mixer, then work into crumbles with your hands.
Spread a good 2/3 of the crumbles on a greased baking tray and press them down to a base with your hands. Alternately, about 10 cm wide strips, spread apple and plum compote on the bottom. Sprinkle the remaining crumbles on top.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) on the lower rack for approx. 45 minutes. Let cool on a cake rack. Serve cut into pieces and dusted with icing sugar.
Whipped cream is delicious with it.