Prepare the crust: In a medium bowl, mix the graham cracker crumbs, 1/4 cup granulated sugar, and melted butter until combined. Press the mixture firmly into the bottom and up the sides of a 9-inch pie plate. Place the crust in the freezer while you prepare the filling.
Make the filling: In a large bowl, beat the softened cream cheese with an electric mixer until smooth. Add the peanut butter and beat until fully combined.
Gradually beat in the powdered sugar and vanilla extract until the mixture is smooth and creamy.
Gently fold in 1 cup of the thawed whipped topping until no streaks remain. Do not overmix.
Spoon the peanut butter filling evenly into the chilled graham cracker crust. Smooth the top with a spatula.
Spread the remaining 1/2 cup of whipped topping over the peanut butter layer. Cover the pie loosely with plastic wrap and chill in the refrigerator for at least 4 hours, or until firm.
Prepare the chocolate ganache: Place the chocolate chips in a small, heatproof bowl. Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer. Pour the hot cream over the chocolate chips. Let it sit undisturbed for 5 minutes.
Whisk the chocolate and cream together until the mixture is smooth and glossy. Let the ganache cool slightly, about 10 minutes, until it thickens enough to spread without running off the pie.
Pour or drizzle the cooled ganache over the chilled pie. Return the pie to the refrigerator for another 30 minutes to allow the ganache to set before slicing and serving.
Notes
For an Oreo crust, substitute 2 cups of finely crushed Oreo cookies (filling included) for the graham cracker crumbs.
If you want a richer chocolate topping, use a 1:1 ratio of chocolate chips to heavy cream for the ganache.
This is a great make-ahead pie; it holds well in the refrigerator for up to three days.