01 - Combine the crushed chocolate sandwich cookies with melted butter in a mixing bowl, stirring until the crumbs are evenly coated. Press the mixture firmly and evenly into the bottom of a 9-inch square or round springform pan. Transfer to the freezer for 15 minutes to firm up.
02 - Using an electric mixer, beat the softened cream cheese, creamy peanut butter, and powdered sugar together in a large bowl until completely smooth and free of lumps. Gently fold in the thawed whipped topping until uniformly incorporated. Spread this mixture evenly over the chilled cookie base.
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 smooth, glossy, and fully melted. Let it cool slightly for a few minutes, then pour the ganache evenly over the peanut butter layer, tilting the pan to spread it into an even coating.
04 - Cover the pan tightly with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow all the layers to set firmly.
05 - Spread the remaining whipped topping over the set chocolate layer in an even layer. Sprinkle with chopped roasted peanuts and chocolate shavings if desired. Slice into squares or wedges and serve well chilled.