1. Trim the tops off the 2 tube cakes to level. Trim the flat end of the bowl cake to level. Cut a hole through the center of the bowl cake the width of the Barbie doll. Place one tube cake, trimmed side up, on a cake plate. Place the second tube cake, trimmed side up on top, and the bowl cake, trimmed side down, on top. Spread 1 cup of frosting between each layer.

2. Remove all clothing from the doll and wrap the doll's hair in plastic wrap. Insert doll into the hole of the bowl cake up to its waist. Use half of the remaining frosting to completely cover the outside of the cakes, evenly smoothing to form the skirt part of the doll.

3. Tint remaining frosting with food coloring to desired colors. Using pastry bags and decorating tips, decorate the skirt and upper half of the doll with colored frosting, as desired. Remove plastic from the doll's hair, and serve.