Start by crushing your choice of 11 ounces of Nutter Butter cookies, shortbread cookies, graham crackers, or Golden Oreos into fine crumbs using a food processor or by placing them in a zip-top bag and crushing with a rolling pin. Transfer the crumbs to a bowl and mix in 1/2 cup melted salted butter until the mixture resembles wet sand. Press the crust evenly into the bottom and up the sides of a 9-inch pie dish. Place the crust in the refrigerator to chill while you prepare the filling.
In a large mixing bowl, beat 8 ounces of softened cream cheese with 1/3 cup granulated sugar until smooth and creamy. Add 1 1/2 cups creamy peanut butter and continue beating until the mixture is well incorporated and fluffy. Next, add 1 cup of the marshmallow fluff and mix thoroughly until smooth and combined.
Gently fold 4 ounces (half) of the Cool Whip into the peanut butter mixture using a rubber spatula. Then fold in 1/3 cup mini marshmallows to add a delightful chewiness to the filling. Be careful to fold gently to maintain the airy texture.
Remove the crust from the refrigerator and spoon the peanut butter filling into the crust. Smooth the top evenly with a spatula. In a separate bowl, whip the remaining 4 ounces of Cool Whip with 2 tablespoons powdered sugar until fluffy. Dollop or pipe the remaining 1 cup marshmallow fluff on top of the pie, then spread or swirl it around to create a decorative, cloud-like topping. Finally, spread the sweetened Cool Whip over the fluff layer.
Sprinkle the top of the pie with crumbled Nutter Butter cookies for a crunchy and visually appealing finish. Cover the pie with plastic wrap and refrigerate for at least 4 hours or overnight to allow the flavors to meld and the filling to set beautifully.