Cut four peanut butter cups in half; coarsely chop remaining cups and set aside. In a large bowl, whisk milk and pudding mix for 2 minutes. Fold in whipped topping until blended.
Fold in chopped peanut butter cups. Spoon into crust. Arrange halved peanut butter cups on top. Refrigerate for at least 15 minutes before cutting. Yield: 8 servings.