Looking at it piece by piece, it was pretty simple.
I happened to own this pan set: http://www.momfinds.com/2010/move-over-oreos-theres-a-new-sandwich-cookie-cake-in-town/
Any round cake pan would work though! So I started off baking two chocolate cakes (using my wonderful slow bake chocolate cake recipe, which I will post another time).
While they baked, I got the ice cream cake layer ready. The icecream was a little too hard still so I tossed in the microwave to soften it up. After cutting a circle to line the bottom of the pan, I sprayed the pan with baking Pam spray. Next, I started scooping the entire quart of cookies and cream ice cream (you could use any flavor obviously) into the pan and, using a spatula, smoothed it down into another cake layer. I covered this in plastic wrap and placed it in the freezer for about 30 minutes (by the time the cakes were done and cooled, I took the ice-cream layer out).
To set the layers up, I placed one cake on a cake board, then (using a knife to loosen the edges) I removed the ice-cream from its pan and placed that atop the previous layer. I topped it with the second cake and then decorated it!
Good luck and let me know if you have any questions about how I made this delicious treat!