This is an extremely rich pie that consists of three very simple layers (plus a candy topping): oreo crust, peanut butter filling, and chocolate mousse. Keep in mind, the peanut butter filling and chocolate mousse recipes are generic ones - I believe they made quite a lot more than was actually necessary for the pie, but I was experimenting, so I wasn't being very precise. I like that this pie is a peanut butter cup pie on multiple levels: (1) It has peanut butter cups on top (2) It has all of the flavors of a peanut butter cup (and then some) (3) It's actually constructed like a giant peanut butter cup: peanut butter filling surrounded by chocolate. 

Anyways, given that I don't actually like peanut butter but I have an absolutely unhealthy love of oreos, this pie is noteworthy for the success of the oreo crust. It was everything I'd hoped it would be. And more.

 
 Oreo Crust
1.5 cups ground oreo cookies (just the chocolate part)
1/4 cup milk powder
2 T sugar
3/4 t salt
4 T butter
1/4 cup heavy cream

First combine the oreo crumbs, the milk powder, the sugar and salt in a stand mixer. Then stir in the butter and add the cream. The mixture will begin to cling together, so pack it into a ball and then press it into the pie dish. Bake for about 15 - 20 minutes at 350. Because of the dark color, it's hard to tell when it's done, and it's better to have this crust underdone rather than overdone because it becomes tough. 
 

Peanut Butter Layer
1 cup peanut butter
3/4 cup butter
3 cups powdered sugar

In a stand mixer, blend the peanut butter and the butter (melted), then gradually stir in the powdered sugar. The mixture will be a crumble that you pack into the crust (as opposed to something more viscous that would be poured).

Chocolate Mousse
12 oz semi-sweet chocolate
1 cup heavy cream

This is my go-to chocolate mousse filling. You just heat the chocolate and cream in a double boiler until combined, then you set it in the fridge until it sets up a bit. Once it's thickened, mix in whipped cream to lighten the mousse to your preference.