Place the butter, powdered sugar, crushed Oreos, milk and vanilla in the bowl of a stand mixer.
Using the paddle attachment, mix all ingredients together.
Let the mixer whip the buttercream for approx 2 minutes until light and fluffy.
Add half of the container of cool whip (4 oz) to the Oreo mixture. Fold to incorporate the cool whip.
Once fully incorporated, pour into the Oreo pie crust.
Top the pie with the remaining cool whip.
Garnish with extra Oreo cookies and crumbs.
Refrigerate for at least 1 hour before serving to help the filling set.