For crust - pulverize the Oreos in a food processor or blender. Pour the Oreo cookie crumbs into a bowl and stir in the melted butter. Press firmly into the bottom and up the sides of a 9" pie pan. Bake at 350° for 10-12 minutes. Cool completely.

For filling - Place the chocolate chips and butter in a large mixing bowl. Top with a fine-meshed metal strainer.

Whisk together the sugar, cornstarch, cocoa powder, and salt in a heavy saucepan. Slowly whisk in the cream, then the egg yolks and milk. Bring to a boil over medium heat, whisking constantly. Let boil for 30-60 seconds.

Pour the pudding through the mesh strainer to remove any lumps. Let sit for a minute or two until the butter and chocolate start to melt. Stir until completely smooth, then add the vanilla.

Pour the chocolate pudding filling into the cooled crust and spread evenly. Cover the surface with plastic wrap and transfer to the refrigerator. Chill for 4-5 hours, or overnight.

For topping: Combine the cream, powdered sugar, cocoa, and vanilla in a deep bowl. Beat with an electric hand mixer at high speed until stiff peaks form.

Spread the chocolate whipped cream over the filling. If desired, garnish the top of the pie with chocolate curls.