Make the Crust: In a food processor, crush the gluten-free Oreos until you have fine crumbs. Combine the crumbs with the melted butter in a bowl and mix well. Press the mixture firmly into the bottom of a 9-inch pie pan. Place in the freezer while you make the filling.
Make the Peanut Butter Filling: In a large bowl, beat the cream cheese and peanut butter together until smooth. Add the powdered sugar and vanilla extract, mixing until everything is well combined and creamy.
Whip the Cream: In a separate bowl, whip the heavy cream until soft peaks form. Gently fold the whipped cream into the peanut butter mixture until it’s fully incorporated.
Assemble the Pie: Pour the peanut butter filling into the Oreo crust, spreading it evenly. If desired, sprinkle some crushed Reese’s Pieces over the top for extra decadence.
Chill: Cover the pie and refrigerate it for at least 4 hours, or preferably overnight, to allow it to set completely.
Make the Whipped Cream Topping: In a clean bowl, whip the heavy cream, powdered sugar, and vanilla extract until stiff peaks form. Spread or pipe the whipped cream over the chilled pie before serving.