You can also make the royal icing with meringue powder instead of egg whites. Use 4 cups powdered sugar, 3 tablespoons meringue powder and 5 to 7 tablespoons water. Using a stand mixer and the whisk attachment, whip most of the powdered sugar with the meringue powder and most of the water. Whip until the icing holds its shape and is bright white (not translucent), 5 to 8 minutes. If it is too soft, add more powdered sugar. If it is too stiff, add a bit more water, drop by drop. You can also substitute royal icing powder. CK Products brand is my favorite.