How to make
Beat the softened butter with sugar into fluffy cream. While continuously whipping, add the egg yolks one at a time and the milk – spoon by spoon. Then add some of the flour with the baking powder and lemon rind. Finally blend in the beaten to snow egg whites, and sprinkle with the remaining flour.
Take 2 tablespoons of the mixture, if desired, and color with cocoa. In a buttered and floured oven dish, pour some of the white mixture. Then pour a thin stream of cocoa in a zigzag pattern. Cover with the remaining uncolored mixture.
Bake the cake in a moderately heated oven and, optionally, when fully baked - sprinkle it with vanilla sugar.
