The cake is called a zebra cake. Basically, you mix yellow and chocolate cake together in the pan in such a way that when the cake is done baking and you cut it into pieces, the pieces look striped. Being one who likes cakes made with lots of real butter, I used the yellow cake recipe and chocolate cake recipe from Mark Bittman's How to Cook Everything cookbook. The yellow cake recipe is super easy to make, while the chocolate cake recipe requires a little bit of extra work (though not much).
Once you have the batter made for each cake, the idea is to put in a few tablespoons of the yellow cake batter into the center of a round cake pan (I used two 9 inch pans for my cake), then put in a few tablespoons of the chocolate batter into the center of the cake pan, and continue until you have what looks like a bulls eye.
The chocolate cake batter ended up being a bit more stiff than the yellow cake. In fact, the yellow cake batter spread very well towards the outer edges of the pan. I would probably add a dab of extra milk to the chocolate batter next time just to help it spread a bit more evenly. Also, the process of spooning in a little bit of batter at a time became a bit time consuming, especially with a toddler clamped to my leg, trying to get my attention.
After the cake was baked, I just made a standard buttercream frosting to frost it with. Maybe if I make it for Evie's birthday I'll get the motivation to try using some fondant. I think it would fun to cover the cake with brown fondant and do white or yellow stripes. Then the party could be wild animal or jungle themed with little animal masks for the kids to put on and wear around. Anyway, below is the final product.
It took a bit more time than I wanted to make this cake, but it tasted really good. Evie liked it, too.