Stir sugar, butter, eggs, vanilla sugar, salt and bitter almond oil until foamy. Mix flour with baking powder in the above made mixture and stir in water. The dough should be rather tough and not too wet. Oil baking pan, and dress with bread-crumbs. Fill in two thirds of the dough. Stir in cocoa in the other part of the dough and add a bit of water until the consistency of the cocoa dough matches that of the light dough. Put the dark dough on the white one and pull a fork in spirals through the dough to achieve a marble structure. Bake 60 minuten at 175 deg C in the hot air oven.