Preheat the oven to 350°F.
In a medium bowl, combine the peanut butter, sugar, and egg.
Pour the peanut butter mixture into a greased 8x8-inch pan.
Bake for 10-15 minutes. Allow to cool completely.
Meanwhile, using a hand mixer, blend the cool whip and cream cheese until creamy.
Fold in most of the crushed Reese's Peanut Butter Cups, reserving some for topping.
Pour the cream cheese mixture over the peanut butter cookie crust.
Sprinkle the extra Reese's Peanut Butter Cup pieces over the top.
Let the pie chill in the refrigerator for 30 minutes and serve.