Heat the oven to 350°F (177°C).
Prepare the crust. Add all 22 Oreos, including the cream centers, to a food processor or blender and process until finely ground. You should end up with about 2 packed cups of crumbs, or 250g. Transfer the crumbs to a large bowl, pour in the melted butter, and stir until evenly combined. Break up any larger pieces that remain. Press the mixture firmly across the bottom and up the sides of an ungreased 9-inch pie dish, creating a compact and substantial crust. Bake for 10 minutes, then set aside to cool while you continue with the recipe.
Prepare the ganache. Put the finely chopped chocolate in a medium heat-safe bowl. Warm the heavy cream in a small saucepan over medium heat, stirring from time to time. As soon as the cream reaches a simmer, take it off the heat and pour it over the chocolate. Leave the mixture undisturbed for 2–3 minutes, then stir gently until completely smooth. Keep the ganache at room temperature so it can cool slightly and begin to thicken.
Prepare the filling. Using a hand mixer or a stand mixer fitted with the whisk attachment, whip the cold heavy cream on medium-high speed until stiff peaks form, about 3 minutes. Transfer the whipped cream to another bowl and set it aside. In the same mixing bowl, with no need to wash it first, beat the cream cheese on medium-high speed until smooth. Add the peanut butter, confectioners’ sugar, and vanilla extract and beat until fully combined. The mixture will be thick. Gently fold in the whipped cream until the filling is smooth, taking care not to knock too much air out of it.
Spoon the peanut butter filling into the cooled Oreo crust and spread it into an even layer.
Pour or spread the slightly thickened chocolate ganache over the peanut butter filling.
If you are not planning to finish the pie with whipped cream, you may sprinkle the chopped peanuts and/or crushed Reese’s Pieces over the ganache while it is still soft so they adhere. If you are using whipped cream, leave the toppings off for now and add them later.
Refrigerate the pie for at least 6 hours and for up to 48 hours. If it will be refrigerated for more than 24 hours, cover it loosely.
Before serving, decorate the pie with whipped cream if desired. Add the crushed Reese’s Pieces and chopped peanuts over the whipped cream.
Cut into slices and serve cold. Cover any remaining pie and refrigerate for up to 5 days.