Get all the ingredients ready. First, prepare the mascarpone balls. Mix mascarpone, sugar, egg yolk and shredded coconut, let the mixture sit for a while.
Form walnut-sized balls. Put it in the freezer for about half an hour.
Beat the butter with the sugar to a white foam, gradually add the eggs and the remaining egg white, sour cream, milk and flour mixed with baking powder.
Divide the dough into two parts. Spread one part on an approx. 12 x 9 in' baking sheet, add cocoa to the other part.
Carefully spread the cocoa part of the dough on the bottom layer of the dough. Take the mascarpone balls out of the freezer and press them into the dough. Bake at 355 °F / 180 °C for about half an hour.
Cook the cream from the listed ingredients, cool while stirring occasionally.
Leave the baked cake to cool.
Spread the cream evenly over the whole cake, put it in the fridge. Sprinkle with grated chocolate.
Cut the cake into cubes, try to cut through the middle of the mascarpone balls. Enjoy!