Beat the softened margarine with egg yolks, sugar, vanilla sugar, salt and lemon zest. Sift flour with baking powder and milk together enter into the egg mass. Add the flour mixed with raisins, currants and whipped up sustained peaks proteins. Pour batter into a greased form, which put in a water bath and cook for 90 minutes, close the lid tightly. Serve with stewed fruit or a fruit sauce.