Mix the egg yolks, sugar and vanilla sugar together. Stir in the butter vanilla flavor, water, oil, flour and baking powder. Beat the egg white with a pinch of salt until stiff and fold into the batter.
Divide the dough in half and add 2 tablespoons of cocoa to one part. Grease a springform pan and always put 2 tablespoons each in the middle. Start with white, otherwise the dough will not slide properly. Always place a pair of cherries between the spoons.
Bake the cake at approx. 160 ° C for 50-60 minutes.