Prepare brownie batter as directed on package; pour into 9-inch pie plate sprayed with cooking spray. Bake 30 min. or as directed. Cool completely. Scoop out center, leaving a 1/2-inch-thick rim around edge and thin layer of brownie on bottom. Reserve removed pieces.
Beat pudding mix and milk with whisk for 2 min. Add 1/3 cup peanut butter; mix well. Stir in Cool Whip. Spoon into crust; top with reserved brownie pieces. **I did not read the directions well, and used the entire container of Cool Whip. The pie was nice and rounded and tasted delicious. So it is a boo-boo I will repeat ;)
Microwave remaining peanut butter in microwaveable bowl on HIGH 1 min.; stir. Drizzle over pie. Refrigerate 2 hours or until pie is firm.