Lightly grease a 9-inch deep dished pie pan with cooking spray and set aside. You could also use a springform pan.
In a medium mixing bowl, combine 2½ cups Oreo cookie crumbs, ½ cup unsalted butter, and ¼ teaspoon 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 8 ounces cream cheese, ¼ cup creamy peanut butter, and ½ cup powdered sugar until smooth.
Fold 2 cups chopped Butterfingers and 8 ounces Cool Whip (thawed) 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 2 (3.4 oz) boxes Chocolate Fudge pudding mix and 2½ cups whole 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 8 ounces Cool Whip evenly on top of the pudding.
Sprinkle with chopped 1 Butterfinger Bar and 2 tablespoons semi-sweet chocolate chips. Then drizzle Chocolate syrup all over the top.
Place in the refrigerator to chill for at least 4 hours or overnight.