Preheat the oven to 350°F (175°C).
In a bowl, mix graham cracker crumbs, sugar, and melted butter until combined.
Press the mixture into the bottom and up the sides of a 9-inch pie pan.
Bake the crust for 10 minutes, then cool completely.
In another bowl, beat the peanut butter and powdered sugar until smooth.
In a separate bowl, whip the heavy cream and vanilla until soft peaks form.
Fold the whipped cream into the peanut butter mixture gently until combined.
Pour the filling into the cooled crust and smooth the top.
Chill the pie in the refrigerator for at least 4 hours before serving.
Garnish with chocolate shavings before slicing and serving.