Make the crust:
In a medium bowl, combine graham cracker crumbs and sugar. Stir in the melted butter until the mixture is evenly coated.
Press the crumb mixture into the bottom and up the sides of a 9-inch pie dish. Use the back of a spoon to pack it down firmly.
Chill the crust in the refrigerator for about 15-20 minutes to set.
Prepare the filling:
In a large bowl, beat the peanut butter, softened cream cheese, and powdered sugar together until smooth and creamy.
Add the heavy cream and vanilla extract, and continue to mix until well combined.
Gradually add the milk to adjust the consistency of the filling, making it smooth and spreadable.
Assemble the pie:
Pour the peanut butter filling into the chilled graham cracker crust. Spread it out evenly using a spatula.
Make the whipped topping:
In a mixing bowl, beat the heavy whipping cream and powdered sugar together until stiff peaks form.
Carefully spread the whipped cream over the peanut butter filling.
Add the chocolate and peanut butter drizzle:
Melt the chocolate chips in a microwave-safe bowl in 20-30 second intervals, stirring in between, until smooth.
Drizzle the melted chocolate over the whipped cream layer.
Optionally, melt peanut butter in the microwave and drizzle over the pie for extra flavor.
Chill the pie:
Refrigerate the pie for at least 3 hours or until it has fully set and is cold.
Serve:
Slice the pie into wedges and serve chilled. You can garnish with additional peanut butter drizzle or chopped peanuts if desired.