Make the crust. Crush the Oreo cookies into fine crumbs using a food processor or blender. Transfer the crumbs to a mixing bowl and stir in the melted butter until evenly combined. Press the mixture firmly into a 9-inch deep-dish pie pan, working the crumbs evenly up the sides first, then pressing the remaining crumbs firmly and evenly across the bottom. Refrigerate the crust while you prepare the fillings.
Make the chocolate ganache. Place the finely chopped chocolate in a bowl. Heat the heavy cream in the microwave until hot, about 30–45 seconds; do not boil. Pour the hot cream over the chocolate and let sit for 2–3 minutes without stirring. Whisk until completely smooth and glossy.Refrigerate the ganache for about 30 minutes while you prepare the other components, stirring every 10 minutes, until thickened slightly and cooled to a soft, spreadable consistency. Make the whipped cream. Using a stand mixer fitted with the whisk attachment (or a hand mixer), whip the cold heavy cream, powdered sugar, and vanilla on high speed until soft peaks form. Transfer to a separate bowl and set aside. Half will be used in the cream cheese filling, and half will be reserved for topping the pie.
Make the cream cheese filling. Beat the softened cream cheese until completely smooth and lump-free. Add the powdered sugar and vanilla extract and mix until fully incorporated, scraping down the sides of the bowl as needed. Gently fold in half of the prepared whipped cream until light, smooth, and fluffy. Set aside.
Whip the chocolate ganache. Once chilled and thickened, whip the ganache just until light, fluffy, and soft peaks form.
Assemble the pie. Spread the cream cheese filling over the chilled crust. Next, add the whipped chocolate ganache and spread into an even layer. Finish with the reserved whipped cream.
Chill. Cover lightly and refrigerate for at least 4 hours until fully set. Sprinkle crushed Oreo cookies over the top for garnish.