Mix brownie mix according to directions on box. Spread 1/2 cup of the mix into one thawed pie crust ( you can always make brownies with the rest). Bake at 375 degrees for 15 minutes or until crust is golden brown and brownie is set. While cooling, mix the cream cheese (best mixes if cheese softened to room temp.) with the powdered sugar. Mix until creamy then mix in the peanut butter until well blended. Mix in 1/2 of the tub of whipped topping until well blended. Spread the mixture into the crust when it is completely cooled. Spread the remaining whipped topping over the filling and if you wish you can top it with miniature peanut butter cups. Refrigerate for at least an hour and enjoy.