01 - Mix creamy peanut butter and powdered sugar in a medium bowl using a fork until mixture reaches crumbly consistency. Set aside 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 together granulated sugar, all-purpose flour, and salt in a saucepan until thoroughly blended.
04 - Gradually whisk whole milk into the dry mixture, stirring continuously until smooth and no lumps remain.
05 - Place saucepan over medium heat, whisking constantly until mixture thickens and begins to bubble. Continue cooking for approximately 4-5 minutes.
06 - Whisk egg yolks in a separate bowl. Gradually pour small amount of hot milk mixture into yolks while whisking rapidly to temper eggs.
07 - Return tempered egg mixture to saucepan, whisking constantly. Cook for 2 additional minutes until filling achieves thick, glossy consistency.
08 - Remove from heat. Stir in unsalted butter and vanilla extract until completely smooth and butter is melted.
09 - Pour warm filling over peanut butter crumb layer in pie shell. Let cool at room temperature for 15 minutes, then refrigerate minimum 2 hours until completely set.
10 - Beat heavy whipping cream, powdered sugar, and vanilla extract using electric mixer until stiff peaks form.
11 - Spread whipped cream evenly over chilled pie surface. Sprinkle remaining peanut butter crumbs over top before serving.