01 - Combine the crushed chocolate sandwich cookies with melted butter in a mixing bowl, stirring until the crumbs are evenly moistened. Press the mixture firmly and uniformly into the bottom of a 9-inch square or round springform pan. Transfer to the freezer for 15 minutes to firm up the base.
02 - Using an electric mixer or whisk, beat together the softened cream cheese, creamy peanut butter, and powdered sugar in a large bowl until completely smooth and free of lumps. Gently fold in the thawed whipped topping with a rubber spatula until just incorporated. Spread the peanut butter mixture evenly over the chilled cookie crust.
03 - Place the semisweet chocolate chips and heavy cream in a microwave-safe bowl. Heat in 20-second intervals, stirring between each burst, until the mixture is glossy and smooth. Let the ganache cool slightly for a few minutes, then pour it evenly over the peanut butter layer, tilting the pan gently to achieve a uniform coating.
04 - Cover the pan loosely with plastic wrap and refrigerate for at least 4 hours, or ideally overnight, to allow the layers to set firmly.
05 - Spread the remaining whipped topping over the set chocolate layer in an even layer. Garnish with chopped roasted peanuts and chocolate shavings if desired. Slice into squares or wedges and serve well chilled.