Make layered cakes. Bake and cool two 6 in. cake layers, two 8 in. cake layers and two 10 in. cake layers.
Prepare icing following recipe directions. Tint 2 cups icing green. Reserve remaining white.
Level, fill and stack cakes on same-size cake circles for 2-layer cakes, 4 in. high. Use spatula to ice cakes smooth, 6 in. in green, 8 in. and 10 in. cakes in white. Spray 8 in. cake with gold Color Mist food color spray. Let dry, about 30 minutes.
Prepare cakes for stacked construction with center core rods and support rods and caps; stack on cake plate.