Make the crust. Pulse the Oreos (cream filling and all) in a food processor until finely crushed. Add the melted butter and pulse until the crumbs look like wet sand. Press firmly into the bottom and up the sides of a 9-inch pie pan. Refrigerate for at least 30 minutes while you make the filling.

Beat the peanut butter base. With a stand mixer fitted with the paddle (or an electric hand mixer), beat the softened cream cheese and ¾ cup powdered sugar until smooth. Add the peanut butter and beat for about 3 minutes, until light and fluffy.

Whip the cream. In a clean bowl, whip the heavy cream until it starts to thicken. Add the remaining 2 tablespoons powdered sugar and the vanilla, then whip to stiff peaks.

Fold and fill. Gently fold the whipped cream into the peanut butter mixture with a rubber spatula just until no streaks remain. Spread the filling into the chilled crust and smooth the top.

Chill. Cover and refrigerate for at least 6 hours (or overnight) until fully set.

Make the ganache (optional). Place the chopped chocolate in a heatproof bowl. Heat the cream in a small saucepan over medium heat just until steaming with small bubbles around the edges (don’t let it boil). Pour over the chocolate, let sit 2–3 minutes, then stir until smooth and glossy. Cool until no longer warm but still pourable.

Top and set. Pour the ganache over the chilled pie and spread into an even layer with an offset spatula. Refrigerate about 1 hour, until set.

Slice and serve. Use a sharp knife, dipping it in warm water and wiping it dry between cuts for clean slices. Serve chilled.