Add the water to the sugar and boil until the syrup spins a thread. Pour the hot syrup very slowly into the beaten white of egg, whipping constantly. Flavor with vanilla and spread the icing on the cake. For chocolate icing, add 2 Tbsp grated chocolate to the warm icing. To tint icing: Lemon juice will whiten icing. The grated rind of an orange will give a yellow color. Strawberry, raspberry or cranberry juice will give a pink shade. Source: Pennsylvania Dutch Cook Book - Fine Old Recipes, Culinary Arts Press, 1936.