For the apple compote, peel, quarter, core and dice apples. Boil up with 250 ml apple juice and 1 vanilla sugar. Simmer for about 5 minutes until soft. Mix 1 pudding powder and 5 tbsp. apple juice.
Stir into the apples and simmer while stirring for about 1 minute. Let the compote cool down.
For the plum compote wash, halve and stone the plums. Bring to the boil with 250 ml apple juice, cinnamon stick and brown sugar. Simmer for about 5 minutes. Mix 1 pudding powder and 5 tbsp. apple juice.
Stir into the plums and simmer while stirring for about 1 minute. Let it cool down. Remove the cinnamon stick.
For the dough, grease a baking tray (approx. 35 x 40 cm). Mix flour, butter in flakes, sugar, 1 vanilla sugar, 1 pinch of salt and egg first with the dough hooks of the mixer, then briefly crumble with your hands.
Good 2⁄3 Press the crumbles onto the sheet metal as a base. Spread the apple compote on one half of the base and the plum compote on the other half. Sprinkle the rest of the crumble on top.
Bake the cake in the preheated oven (electric oven: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 45 minutes. Let cool off. Cut the cake between the compote halves. Cut apple and plum cake in half lengthwise.
Cut each apple pie plate into 4 oblong triangles. Let cool off.
For the filling, stir mascarpone and quark until smooth. Mix 75 g sugar and cream setting agent and stir in with the whisks of the mixer. Spread each plum cake plate with the cream. Place apple pie triangles on top.
Chill for about 2 hours.
Cut into cake pieces along the apple triangles. If necessary, cut the large cake pieces in half crosswise. Decorate if necessary.