Lightly grease a 9-inch deep dished pie pan with cooking spray and set aside. In a medium mixing bowl, combine the Oreo cookie crumbs, melted butter, and salt. Pour the crumb mixture into the prepared pie pan and press it firmly into the bottom of the pan and up the sides. Then place it in the refrigerator to chill while the filling is prepared.
In a large mixing bowl, beat the cream cheese, peanut butter, and powdered sugar until smooth. Fold 2 cups of chopped Butterfingers and half of the thawed Cool Whip into the peanut butter mixture with a rubber spatula until evenly combined and there are no more streaks of white. Transfer the Butterfinger mixture to the prepared crust and spread it into an even layer.
In a medium mixing bowl, whisk together the chocolate fudge pudding mix and milk for 2 to 3 minutes until it thickens. Carefully spread the chocolate pudding layer evenly on top of the Butterfinger cream cheese layer. Spread the remaining Cool Whip evenly on top of the pudding.