1. Prepare cake, 1 recipe at a time, using 2 jellyroll pans; bake as directed.
2. Cut out 3 layers for each tiered cake, using 3-inch, 1 1/2-inch, and 1-inch round cutters. Stack 3 tiers, from largest to smallest. Place each tiered cake on a wire rack over a shallow bowl or pan.
3. Prepare Poured Fondant, 1 recipe at a time; tint with food coloring paste, if desired. Quickly pour fondant over cake tiers, completely covering tops and sides. Reheat excess fondant, if necessary. Continue until tiers are evenly coated. Let dry before decorating. (If necessary, touch up fondant with a hot, wet spatula before letting it dry.)
4. Pipe a small shell border with Buttercream Frosting, using metal tip #16. Garnish, if desired.