Follow directions for cake mixes as directed & fill batter bowl with TWO of the cake mixes; then make 2 round cakes w/the 3rd cake mix. The 3rd cake mix is necessary b/c if you use a Barbie doll as the center rather than the cake pick, she will be too tall for the skirt. Bake 2 round pans as directed, but batter bowl cake will require almost an hour to bake through completely. Use a bamboo stick or straw to check the...the...done-ness.
Sorry, I didn't take pics as I went, but I have one of the assembly. Once you remove the batter bowl cake, cut off the top so it will sit flat on top of the round cake. This is where my engineer hubby helped out >> He cut 2 long straight cuts down the center of the cake, then pushed the cake out the bottom to push Barbie through. This helped keep the stability of the cake, rather than just shoving poor ole' Barbie in there like I was gonna do (the "Joy" way).
Here's a pic of 1st step assembly:
...And here's proof that it was worth it all! My little doll got her wish!!