For the streusel, mix any amount of flour, oat flakes, salt, the two types of sugar and cinnamon. Add the butter and process everything into sprinkles of any size, either with the hand mixer or simply with your fingers.
Then chill until further use.
Now preheat the oven to 180 ° C top / bottom heat.
For the dough, first beat the eggs with the salt until foamy, then gradually pour in sugar and brown sugar and continue beating until the mixture becomes thick and creamy. Gradually let the oil run in, beating more and more.
Then mix the flour, starch, baking powder and grated chocolate and stir into the egg mixture with the milk.
Spread about 2/3 of the dough on the prepared tray. Stir in the cocoa into the rest of the batter, spoonful on top and marbled a little.
Finally, distribute the cherries on top and sprinkle the crumble on top as evenly as possible.
Bake in the preheated oven for about 25-30 minutes.