I used a chocolate cake mix that he picked out, and baked it in two 8" round cake pans. I baked the cakes according to the package directions.
While they were cooling, I put the ice cream on the counter to soften. I should have put the first cake layer in the freezer before starting to assemble, but that's what I get for not following directions.
Anyway, I used a 8" Springform pan and lined it with two pieces of plastic wrap. I put the first cake in the bottom and then put in a layer of softened ice cream. You could mix and candy, fruit, or nuts into the ice cream, but I left it plain.
I added a final frosting layer of whip cream because regular buttercream tends to be too sweet for both me and Deputy D. To make it pretty, I added chocolate chips to the top. Then, I put the cake back into the freezer until we were ready to eat.
Remove the cake 30-45 minutes before eating.