Begin by placing your Oreo cookies in a food processor and pulse them until they become fine crumbs. In a separate bowl, melt 6 tablespoons of unsalted butter, then combine it with the crushed cookies. Stir until evenly coated. Press this mixture firmly into the bottom of a 9x13-inch baking dish to form a solid crust.

In a large mixing bowl, beat together 8 ounces of softened cream cheese, 1 cup of peanut butter, 3/4 cup of powdered sugar, and 1 teaspoon of vanilla extract. Use an electric mixer on medium speed until the mixture is smooth and creamy, about 3-5 minutes. Carefully fold in half of an 8-ounce container of thawed whipped topping until fully combined and fluffy.

Spread the creamy peanut butter mixture evenly over the prepared Oreo crust in your baking dish.

In a separate mixing bowl, combine the contents of 2 boxes (3.4 ounces each) of instant chocolate fudge pudding with 3 cups of cold whole milk. Whisk the mixture vigorously for about 2 minutes until it thickens to a pudding-like consistency. Pour this layer over the peanut butter layer, spreading it evenly with a spatula.

Cover the dish with plastic wrap and place it in the refrigerator. Allow the Peanut Butter Lasagna to chill for at least 2 hours, ideally overnight.

Before serving, remove the dish from the refrigerator and spread the remaining 8 ounces of whipped topping evenly over the top layer. Garnish with crushed peanuts or chocolate sauce if desired.