01 - Combine creamy peanut butter and powdered sugar in a medium bowl. Mix with a fork until crumbly texture forms throughout. 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. Press gently to create an even layer.
03 - Whisk together granulated sugar, all-purpose flour, and salt in a saucepan until thoroughly blended. Gradually pour in whole milk while whisking continuously to prevent lumps from forming.
04 - Place saucepan over medium heat. Whisk constantly until mixture thickens noticeably and begins to bubble. Continue cooking for approximately 4 to 5 minutes, ensuring smooth consistency.
05 - Whisk egg yolks in a separate bowl until smooth. Slowly add approximately 1/2 cup of the hot milk mixture to the yolks while whisking rapidly to prevent curdling.
06 - Return tempered egg mixture to the saucepan, whisking constantly. Continue cooking over medium heat for 2 additional minutes until filling becomes thick and glossy. Remove from heat immediately.
07 - Stir unsalted butter and vanilla extract into hot filling until completely melted and incorporated. The mixture should appear smooth and creamy.
08 - Pour warm filling over peanut butter crumb layer in pie shell. Allow to cool at room temperature for 15 minutes, then refrigerate for minimum 2 hours until completely set and firm.
09 - Beat heavy whipping cream, powdered sugar, and vanilla extract with electric mixer until stiff peaks form. Do not overbeat or cream may become grainy.
10 - Spread whipped cream topping evenly over chilled pie surface. Sprinkle remaining peanut butter crumbs generously across top before slicing and serving.