01 - Mix creamy peanut butter and powdered sugar in a medium bowl using a fork until crumbly texture forms. Reserve mixture for later use.
02 - Distribute half of the prepared peanut butter crumbs evenly across the bottom of the baked and cooled pie crust.
03 - Whisk granulated sugar, all-purpose flour, and salt together in a saucepan until thoroughly blended.
04 - Gradually whisk whole milk into dry mixture until smooth. Place saucepan over medium heat and cook, whisking constantly for 4-5 minutes until mixture thickens and begins to boil.
05 - Whisk egg yolks in a separate bowl. Slowly incorporate a small amount of the hot milk mixture while whisking continuously to temper the eggs.
06 - Return tempered egg mixture to saucepan, whisking constantly. Cook for 2 additional minutes until filling achieves thick, glossy consistency. Remove from heat and stir in butter and vanilla until smooth.
07 - Pour hot filling over peanut butter crumb layer in pie shell. Cool at room temperature for 15 minutes, then refrigerate for minimum 2 hours until completely set.
08 - Beat heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form. Spread whipped cream evenly over chilled pie surface.
09 - Sprinkle remaining peanut butter crumbs over whipped topping before serving. Serve chilled.