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 evenly into the bottom of a 9-inch springform pan or square baking dish. 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 with a rubber spatula until uniformly combined. Spread this mixture in an even layer 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 for a few minutes, then pour it evenly over the peanut butter layer, tilting the pan gently to spread.
04 - Cover the pan tightly with plastic wrap and refrigerate for at least 4 hours, or ideally overnight, until all layers are fully set and firm.
05 - Spread the remaining whipped topping evenly over the set chocolate layer. Sprinkle with chopped roasted peanuts and chocolate shavings if desired.
06 - Cut into squares or wedges with a sharp knife, wiping the blade clean between cuts for neat portions. Serve well chilled.