01 - Combine creamy peanut butter and powdered sugar in a medium bowl. Mix with fork until mixture reaches crumbly consistency. Set aside for later use.
02 - Distribute half of prepared peanut butter crumbs evenly across bottom of cooled baked pie crust. Press gently to create compact layer.
03 - Whisk together granulated sugar, all-purpose flour, and salt in saucepan. Gradually incorporate whole milk while whisking continuously until smooth mixture forms.
04 - Place saucepan over medium heat. Whisk constantly until mixture thickens and begins to boil, approximately 4 to 5 minutes. Monitor carefully to prevent scorching.
05 - Whisk egg yolks in separate bowl. Slowly add small amount of hot milk mixture while whisking rapidly to temper eggs. This prevents curdling when combining.
06 - Return tempered egg mixture to saucepan, whisking constantly. Cook 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 butter melts completely and mixture is smooth.
08 - Pour warm filling over peanut butter crumb layer in pie shell. Let cool at room temperature for 15 minutes, then refrigerate for minimum 2 hours until completely set.
09 - Beat heavy whipping cream with powdered sugar and vanilla extract until stiff peaks form. Spread generously over chilled pie surface.
10 - Sprinkle remaining peanut butter crumbs over whipped topping. Slice and serve immediately, or keep refrigerated until ready to serve.