Make a dough from yolk, sugar, vanilla sugar, oil, nuts, possibly cocoa, flour, baking soda, baking powder and cinnamon. Roughly grate the zucchini and add. Beat in the egg whites and fold in. Bake at 170 - 180 ° C top / bottom heat for 30 - 45 minutes.
Brush the cooled cake with jam (preferably a sour one like currant or raspberry) and then glaze with chocolate icing.