Add the 24 OREO cookies to the bowl of a food processor. Process into fine crumbs. Then drizzle in the melted butter, and pulse until the crumbs combine with the butter. Press the crumb mixture into the bottom and sides of a deep-dish, 9-inch pie plate. Put it into the freezer while you prepare the filling.
PREPARE THE FILLING:
Add the heavy cream to a large bowl. Use an electric mixer to beat the cream to stiff peaks (1 or 2 minutes). Set the whipped cream aside.
In a separate bowl, use the electric mixer to combine the cream cheese, powdered sugar and vanilla until smooth and well-combined. Transfer the mixture to the bowl with the whipped cream, and use a rubber spatula to fold them together.
Add 9 OREO cookies to a zip baggie, and use a rolling pin or meat mallet to smash the cookies into small pieces. Stir the crushed cookies into the filling mixture. Scrape the filling into the frozen crust, and smooth the top. Refrigerate.
ADD THE TOPPING:
In a medium bowl, use an electric mixer to whip the heavy cream to stiff peaks. Add the whipped cream to a piping bag with a decorative tip, and pipe swirls along the edge of the pie (alternately, you can just spoon dollops of the whipped cream onto the pie). Place a whole OREO into each swirl of cream. Refrigerate until ready to serve.