Since I was making chocolate cake and not putting any cookies in the batter, I decided to make some whipped cream to fill the cupcakes so it would be more like an Oreo--you know, chocolate with cream center. This turned out to be wholly unnecessary and next time I will definitely skip the whipped cream. It just got lost in the cupcake and frosting; it wasn't bad, but, like I said, just unnecessary. I made a cooked flour buttercream for the frosting because I thought that would taste more like an Oreo cream center than an American buttercream. Now, I know having flour in your frosting sounds wrong, but it is suuuuuuuch good frosting! Trust me! It comes out fluffy and creamy and delicious. Cooked flour buttercream is pretty simple -- click here for a good recipe/tutorial for it if you're interested in making some. Anyway, I put some Oreos in the food processor to chop them and added the really fine powdered bits to the frosting early on, then folded in some bigger chunks once the frosting was done. Unfortunately I was in a bit of a hurry getting these done so I don't have any frosting pics.
I piped the frosting in a simple swirl [note: if you're going to pipe your frosting, make sure your cookie bits are all small enough to fit through the tip! I had a few get stuck and mess up my swirls] and finished the cupcakes off with a mini Oreo on top :)
Anyways! The cupcakes were really, really good! I highly recommend putting the half-Oreo at the bottom of the cupcake; it brought in a nice cookie crunch (well, okay, it was actually fairly soft after being baked) that definitely made the whole cupcake say "Cookies N Cream!" Also, personally, I think I made the right choice with the frosting, it really tasted like cookies n cream as well. And how could a mini Oreo topper ever be wrong? :) YUM!