Preparation Steps

• Chill a large metal mixing bowl and beaters in the freezer for 10 minutes. Line a 9-inch springform pan with a round of parchment on the base and lightly butter or spray the sides.
• Make the crust: Place the cookies in a zip-top bag and crush to fine crumbs with a rolling pin (or use a food processor). Stir the crumbs with the melted butter until evenly moistened. Press firmly into the bottom and about 1 inch up the sides of the pan. Freeze for 15 minutes to set while you prepare the filling.
• Start the ganache: Warm 1/4 cup heavy cream in a small saucepan over low heat just until steaming, 1–2 minutes (do not boil). Pour over 6 ounces finely chopped chocolate in a heatproof bowl. Let stand 2 minutes, then stir until smooth and glossy. Cool to room temperature, about 10 minutes.
• Whip the cream: In the chilled bowl, beat 1 1/2 cups cold heavy cream with the powdered sugar on medium-high until stiff peaks form, 2–3 minutes. Scoop about 1 generous cup into a separate bowl for topping; keep chilled. The remaining whipped cream will be folded into the filling.
• Make the marshmallow base: Beat the cream cheese and granulated sugar on medium-high until completely smooth and fluffy, 1–2 minutes. Mix in the vanilla, espresso powder, and marshmallow creme until silky with no streaks.
• Finish the filling: Whisk the cooled chocolate ganache into the marshmallow base until fully combined. Fold in half of the reserved whipped cream for the filling to lighten, then gently fold in the rest just until no white streaks remain. Stir in the remaining 2 ounces of finely chopped chocolate for texture.
• Assemble and chill: Spoon the filling into the cold crust and smooth the top. Tap the pan lightly on the counter to release air pockets. Refrigerate until set, 2–3 hours (or 1 hour in the freezer for a faster set).
• Top and serve: Swirl the reserved whipped cream over the chilled pie and finish with crushed Oreo cookies if using. For the cleanest slices, warm a knife under hot water and wipe between cuts.