In a bowl, mix peanut butter and powdered sugar with a fork until crumbly. Sprinkle half into the baked pie crust.

In a saucepan, whisk milk, sugar, cornstarch, and salt over medium heat until thickened.

Slowly add a little hot mixture into egg yolks to temper, then pour back into saucepan. Cook 2 more minutes, stirring constantly.

Remove from heat and stir in butter and vanilla.

Pour custard into the crust over peanut butter crumbles. Let cool to room temp, then refrigerate for at least 4 hours.

Top with whipped cream and sprinkle with remaining peanut butter crumbles before serving.