Preheat oven to 350°F (175°C). In a medium bowl, combine graham cracker crumbs, melted butter, and granulated sugar. Press evenly into the bottom and up the sides of a 9-inch pie plate.
Bake the crust for 8-10 minutes, or until lightly golden. Let cool completely.
In a large bowl, beat together the softened butter and peanut butter until smooth.
Gradually beat in the powdered sugar, alternating with the milk, until well combined and smooth. Stir in the vanilla extract.
Gently fold in the melted chocolate chips until just combined.
Spoon the peanut butter fudge filling into the cooled graham cracker crust, spreading evenly.
Chill the pie in the refrigerator for at least 2 hours, or until firm.
Slice and serve. Drizzle with extra melted chocolate or peanut butter if desired.
Notes
For a richer flavor, you can toast the graham crackers slightly before making the crust. This pie is best served chilled.