01 - Combine the crushed chocolate sandwich cookies and melted butter in a medium bowl, stirring until the crumbs are evenly moistened. Press the mixture firmly into the bottom of a 9x9-inch baking dish to form an even, compact layer. Place the dish in the refrigerator to chill while preparing the next layer.
02 - In a large mixing bowl, beat the softened cream cheese, creamy peanut butter, and powdered sugar together using an electric mixer or whisk until completely smooth and lump-free. Gently fold in 1 cup of thawed whipped topping with a spatula until evenly incorporated. Spread the peanut butter mixture in a smooth, even layer over the chilled cookie crust.
03 - In a separate bowl, whisk the instant chocolate pudding mix and cold milk together vigorously for about 2 minutes until the mixture thickens and becomes silky. Pour the pudding over the peanut butter layer and spread it evenly to cover the entire surface.
04 - Spread the remaining 1 cup of whipped topping over the pudding layer in an even layer. If desired, drizzle with the melted peanut butter and sprinkle with chocolate shavings or mini chocolate chips for garnish.
05 - Cover the baking dish tightly with plastic wrap and refrigerate for at least 3 hours, or until all layers are fully set and firm to the touch.
06 - Using a sharp knife, cut the chilled dessert into squares. Serve immediately while still cold.