In a large mixing bowl, combine the peanut butter and cream cheese. Using an electric mixer, beat them together until smooth and creamy.
Gradually add in the powdered sugar and continue mixing until fully incorporated.
Pour in the milk and mix until the mixture is smooth and well-blended.
In a separate bowl, take the Cool Whip and gently fold it into the peanut butter mixture.
Once the filling is ready, pour it into the premade chocolate crust and smooth the top.
Cover the pie with plastic wrap and refrigerate for at least 4 hours, or ideally overnight.
Before serving, top with chopped peanut butter cups. Slice, serve, and enjoy!
