Prepare the Crust:
In a bowl, combine the graham cracker crumbs with melted butter until evenly mixed. Press this mixture into the bottom and sides of a pie dish to form your crust. Set it aside to firm up while you prepare the filling.
Mix the Filling:
In a large mixing bowl, beat together the softened cream cheese, peanut butter, and powdered sugar until smooth and creamy. Add the vanilla extract. Slowly fold in the whipped cream until well combined, taking care not to deflate the mixture.
Assemble the Pie:
Pour the peanut butter filling into the crust, smoothing the top with a spatula.
Chill:
Cover the pie with plastic wrap and place it in the refrigerator for at least four hours, or overnight if possible. This is essential for it to set properly.
Decorate:
Just before serving, drizzle chocolate ganache over the top, dollop with additional whipped cream, and sprinkle with chopped peanuts if desired.