Begin by finely crushing about 20 peanut butter sandwich cookies in a food processor until you have a fine crumb. Melt 4 tablespoons of butter and combine it with the cookie crumbs until fully mixed. Press this mixture firmly into the bottom of an 8x8-inch baking dish, creating an even layer. Place the dish in the freezer for 30 minutes to set the crust.

While the crust is chilling, prepare the chocolate pudding layer. In a mixing bowl, combine one package of instant chocolate pudding with 1½ cups of milk. Using a whisk, mix thoroughly for about 2 minutes until the mixture begins to thicken. Once combined, cover the bowl and refrigerate it for 10-15 minutes to ensure a consistent texture.

In a separate mixing bowl, beat together 8 ounces of softened cream cheese and 1 cup of confectioners' sugar using an electric mixer until smooth and creamy. Add ½ cup of creamy peanut butter and 1 teaspoon of pure vanilla extract, mixing until fully blended.

Remove the crust from the freezer and spread the creamy peanut butter mixture evenly over the cookie base. Follow this with the chilled chocolate pudding, smoothing it out carefully to form an even layer. Finally, spread 1 cup of Cool Whip on top.

To allow the layers to firm, cover the baking dish with plastic wrap and refrigerate for at least 2 hours. For a quicker option, you can freeze the assembled bars for 30 minutes.

Just before serving, sprinkle some crushed peanut butter sandwich cookies and milk chocolate or peanut butter chips on top. Using a warm knife, cut the bars into squares.