In a food processor, pulse the Oreos into fine crumbs (it’s easier if you break them up first).
Pour crumbs into a large bowl and add the melted butter, stir to combine.
Pour the mixture into a round baking dish. Using your hand or the back of a spoon, gently press the crumbs into the bottom and up the sides of the dish to make a thick crust.
Place it in the freezer to set while you make the filling.
Using a hand mixer, mix the peanut butter, sugar, cream cheese, and milk in a large bowl.
Beat until the mixture is completely smooth, then gently fold in the Cool Whip.
Remove pie crust from the freezer and add the pie filling onto the crust, swirling to make it completely smooth on top.
Top with chocolate syrup and Reese’s peanut butter topping if desired.
Freeze for at least 4 hours or ideally overnight.
Remove from the freezer and let sit out for about 20 minutes to thaw before serving. Enjoy!