I was a Pampered Chef consultant, and my sister was getting married. I wanted to make her a doll cake for her shower. I checked out a bunch of sites online, and found one that described step by step how to bake, prepare, and frost a Bridal Barbie Doll cake. This site also described in detail about all the frosting layers needed, and the essential "crumb layer".
First I whipped together a basic Betty Crocker cake mix, and set to bake in the oven at 350 for about 30-45min. The mixture baked in two glass bowls. Both Pampered Chef's the small batter bowl and large classic batter bowl. The large is a 4cup size, and the small a 2cup size. The bottom layer was the larger of the two sized bowls.
After removing from the oven, I set to cool for an hour, then removed each from the bowls, wrapped the baked cakes in seran individually, and placed in the freezer for about 45 minutes. During this time I decorated the doll pick. Bought a doll pick (half a doll with the legs gone) at the craft store.
After the two cakes had cooled and chilled in the freezer, I set the larger one bottom up on the platter it would be served on, and the smaller of the two cakes on top of that also bottom side up. I made sure they stuck together without falling apart by using toothpicks to hold the two layers together. The smaller of the two shapes (the one on the very top) I had to shave down with the serrated bread knife and chill another half hour of so as it started to fall apart on me.
After assembling the layers, I chilled again another half hour, and then started on the crumb layer. Light layer of frosting over the whole thing, and chilled in between each layer of frosting about 15minutes. (This is the part that took the longest as I didn't want the frosting to start melting off.) I used regular Betty Crocker White frosting and chilled in the fridge for an hour before starting. Chilled again between each layer of frosting, and the final decorating. By the time I got to the fancy frosting tips around the doll to create the look of the dress, the frosting on the overall layers was pretty hardened.
Stuck the doll in before doing the final fancy frosting, and removed a shelf in my fridge to chill the whole thing overnight until the last minute right before the party the next morning. (It was a brunch, so that made it easier.) It was tricky to transport. I had to have my husband drive and I held the platter on my lap. I don't recommend this if you can avoid transporting. Good luck!