Beat the eggs and 150 g sugar with the whisk of the hand mixer until creamy. Mix flour, cocoa and baking powder. Sieve several portions onto the egg mixture and fold in. Spread on a baking tray (approx. 36 x 41 cm) lined with baking paper.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) on the 2nd rack from below for approx. 20 minutes. Turn the sponge onto a cloth sprinkled with sugar, remove the baking paper, let the sponge cool down.
Whip the quark, mascarpone, vanillin sugar and 80 g sugar until creamy. Spread the cream on the sponge cake and chill. Stir starch with 2 tbsp. water until smooth. Place the cherries in a sieve, collecting the juice.
Bring juice and 40 g sugar to the boil in a small pot. Stir in starch and let it simmer for about 2 minutes, add cherries, remove from the heat. Let the compote cool down.
Cut sponge cake base with mascarpone cream into cubes, decorate with cherry compote and serve.