Make and bake the cakes. Mix two box mixes of cake mix (you can mix and match or use all one flavor, totally up to you.The size of cake will fit any Barbie-size princess doll or Barbie doll. A ceramic or stoneware mixing bowl will work great. Just make sure the bowls you are using are oven safe. That’s all you’ll need for the base of the cake, or the skirt. Find your “molds”. The “skirt” of the cake is baked in one or two 8″ cake pans and an oven-safe glass bowl (or two glass bowls, one medium-sized and one small sized).