Meringue is deceptive; as elegant and decorative as it may look, its simple taste reflects its simple composition, created from nothing more than egg whites, sugar syrup, and cream of tartar. Meringue lends itself to hints of subtle flavorings -- vanilla, orange-blossom water, jasmine, rosewater, or a delicate liqueur could add an appealing undertaste -- but it is as much of a treat by itself. The Italian Meringue recipe used here holds its shape well, making it ideal for decorative applications. Martha Stewart Living food editor Susan Spungen uses it to emulate the spiky petals of a chrysanthemum on a stunning wedding cake.You'll need a solid base to hold a cake of this size; but aluminum foil or an unattractive caterer's tray will detract from the luxurious beauty of the cake. One solution is to coat a plywood base with royal icing, which adds a symmetry and continuity to the pristine white of the meringue. Eighteen batches of Moist Yellow Cake batter are needed to yield two 6-inch round layers, two 12-inch layers, and two 18-inch layers. Fill each 6-inch pan with 2 cups of batter; fill each 12-inch pan with 8 cups of batter; fill each 18-inch pan with 18 cups of batter.