Oreo Cake that (vaguely) looks like a GIANT OREO

This year my sister-in-law Hilary made her own birthday cake with an Oreo theme.  When, just a few days later, my co-workers proposed an all-Oreo celebration, I offered to make the same cake.  (My co-worker Nick always brings Oreos on Tuesday nights and Saturdays, so for his birthday we went all out!)

The cake got good reviews all around, so it is definitely worth making again.  Note: because of the ganache on top you need a really sharp knife to cut it.  You probably don't need the ganache, though.  It would be delicious even without!

Here's the original recipe:
http://allrecipes.com/recipe/136264/chocolate-covered-oreo-cookie-cake/

I added more cookies and couldn't figure out how to make the edges as neat as the photo in the original recipe....so here's my version:

Ingredients

• 1 chocolate cake mix and ingredients it calls for (I used a dark chocolate mix, to look more Oreo-like)
• 1 (8 o) package cream cheese, softened 
• 1/2 cup sugar
• 2 cups Cool Whip, thawed 
• 15+ Oreo Cookies, coarsely crushed (I used 15, but think that even more would work great!)
• 4 oz Semi-Sweet Bakers Chocolate 
• 1/4 cup butter 

Directions:

1. Heat oven to 350 degrees F
2. Prepare two 9-inch pans as directed on mix package.  (Mine said to grease and flour, but I didn't want to risk any white flour on my giant Oreo, so I used a half-and-half mixture of flour and cocoa powder.)
3. Bake cakes as directed on package
4. Cool cakes in pans, then remove from pans
5. Cut one of layers to level it, if needed
6. Beat cream cheese and sugar until blended (I used a whisk, but you definitely could use a mixer)
7. Crush cookies (I just put them in a freezer bag and crushed them.)
8. Gently stir cookie pieces and Cool Whip into cream cheese mixture
9. Assemble cake: Place one layer on bottom, spread "filling," top with other layer
10. Add ganache, if desired: Microwave butter and chocolate until melted and then stir together.  Let cool a few minutes if you want a more spreadable version.  I wanted mine to drizzle down the edges, so I immediately spooned it in the middle and spread in circles outward to get that effect. 
11. Keep cake refrigerated.