Here are the instructions. They are printable on the site. Photo on the site too. Have fun!
HOW TO MAKE A BARBIE DOLL CAKE
Here are Dale Koppel's step-by-step instructions for creating a Barbie Doll Cake at home.
Prepare batter for any flavor two-layer cake; feel free to use a mix. Bake in 2 (8-inch-round) cake pans according to package directions.
Cool the cakes on wire racks according to package directions. Then slice each cake crosswise into three layers (that's a total of six layers).
Put frosting between the layers so the finished cake is as tall as Barbie measures. You can do this in a deep cake pan so the layers line up well.
Pond's Tip: Measure the Barbie you're going to be using from her hips to her toes (yep, her tippy toes). That's how high your finished cake will need to be. Use a frosting mix and prepare it according to package directions -- any flavor will do. The frosting should be thick enough to stabilize the stacked layers.
Wrap the outside of the cake with a layer of wax paper, so that the layers are perfectly straight. Freeze the cake overnight or until it's solid.
Pond's Tip: When frozen, the cake can be manipulated without it breaking.
Use a pair of tongs to cut a hole in the stacked layers from top to bottom. The hole should have the same diameter as the Barbie doll.
Pond's Tip: If the hole is too small, and you have to force Barbie into it, the cake will crack when it defrosts. So, make sure the hole is big enough.
Remove cake from pan if you used a pan for stacking the cake layers. Trim the top of the cake to create a skirt shape.
Wrap the doll in plastic. Insert Barbie so that the cake comes just up to her hips.
Pond's Tip: If you wrap the doll in plastic wrap, it will keep the doll from touching any part of the cake. And Barbie will be a lot cleaner when you take her out of the cake.
Another Pond Tip: "Keep a blouse on your Barbie, so you only have to decorate the cake part as the skirt."
Remove the wax paper from the cake. Use a decorating spatula to spread frosting over the cake and create Barbie's skirt. Use a pastry bag with decorative tip of choice to decorate further.
Pond's Tip: Be creative. Use more than one color of frosting. Embellish it with colored sprinkles and candies. Use your imagination.