I saw a cake similar to this several years ago. Instead of looking up instructions on how to properly make the cake, I just made it. This is definitely one of the messier cakes that I've made, but it was a lot of fun to make!
The cake consists of two layers of chocolate cake, a layer of vanilla ice cream, and chocolate frosting in the expected locations. The version of the cake that influenced this messy cake was decorated like an Oreo cookie, so I kept that as a decorating guideline. Instead of "Oreo" I wrote "Happy Birthday" since it was for a birthday.
If you plan to make this, here are some tips: Make the cake at the location where the cake will be served; it will melt during a 20 minute car ride in the summer. Try to freeze the ice cream layer in a circle cake pan lined with wax paper so it has the proper shape. Be sure to rearrange the contents of your freezer before assembling any of the cake pieces. You can use any combination of flavors to make this cake; I'm guessing cookies and cream ice cream would be amazing!
Ice Cream Sandwich Cake
Two round cakes
1/2 gallon ice cream
One batch of frosting
Make your frosting.
Soften your ice cream. I'm assuming it isn't necessary to mix up the ice cream in a mixer, but it sure was fun. Such a lovely texture!
Place the bottom layer of the cake on whatever you plan to serve the cake on. Spread a layer of frosting around the sides of the cake. Either cover the entire top of the cake or just enough so the cake doesn't show under the ice cream.
Spread a layer of ice cream on the cake. (Or, if you followed the tip, place the layer of ice cream on the cake.) Place the incomplete cake in the freezer.
Place the top layer of cake on some paper towels. Spread a nice layer of frosting on top. Decorate however you want to decorate it.
Remove the bottom of the cake from the freezer and carefully place the top layer of the cake on top. Spread a layer of frosting around the sides of the top layer of cake.
Keep frozen until you are ready to serve!
Note: The frosting that I used was the new Wilton Decorator's Frosting with 3 Tablespoons of cocoa powder added.
Used to create this cake: Food Network 9-In. Round Cake Pan. I love the Food Network pans from Kohls!