Make the Filling: Beat peanut butter, powdered sugar, and softened cream cheese until smooth.
Whip the Cream: In a chilled bowl, whip heavy cream to stiff peaks.
Combine: Fold whipped cream into peanut butter mixture gently until no streaks remain.
Fill the Crust: Spoon filling into graham cracker crust and smooth top.
Make Ganache: Microwave chocolate chips and milk in 30-second bursts, stirring until smooth. Stir in vanilla.
Top the Pie: Pour ganache over filling, tilting to coat evenly.
Chill: Refrigerate for at least 4 hours, or overnight.
Serve: Garnish with peanuts if desired. Slice and serve cold.