In a medium saucepan, combine sugar, milk, butter, and cocoa. Bring to a boil, and cook for 1 1/2 minutes. Remove from heat, and stir in peanut butter, oats, and vanilla.
On a piece of wax paper, drop 6-8 tablespoon sized cookies. (I used 6 on my pie & ate 2 - oops) Set aside.
Lightly spray a deep dish pie plate with non-stick spray. Using your hands, spread the cookie dough around & up the diameter of the dish. As it cools, the cookie dough will begin to set so you may need to wait 5-7 minutes for the dough to cool enough to stay in place it will. Refrigerate to set.
For the filling:
In a large bowl, mix together peanut butter, cream cheese and sugar. Stir whipped topping into peanut butter mixture. Whisk until smooth and no lumps remain.
Pour filling into cookie dough pie crust and refrigerate for about 3 hours until pie is firm.
Garnish with the extra cookies & whipped cream (if desired).