01 - Combine creamy peanut butter and powdered sugar in a medium bowl. Mix with a fork until mixture reaches crumbly consistency. Reserve for later use.
02 - Distribute half of the prepared peanut butter crumbs evenly across the bottom of the cooled baked pie crust. Press gently to adhere.
03 - In a medium saucepan, whisk together granulated sugar, all-purpose flour, and salt until thoroughly blended.
04 - Gradually whisk whole milk into the dry mixture, ensuring no lumps remain. Continue whisking until completely smooth.
05 - Place saucepan over medium heat. Cook while whisking constantly until mixture thickens and begins to bubble, approximately 4 to 5 minutes.
06 - Whisk egg yolks in a separate bowl. Gradually incorporate a small amount of the hot milk mixture while whisking continuously to prevent curdling.
07 - Pour tempered egg mixture back into the saucepan while whisking constantly. Continue cooking for 2 additional minutes until filling becomes thick and glossy.
08 - Remove from heat. Stir in unsalted butter and vanilla extract until butter melts completely and mixture is smooth.
09 - Pour warm filling over the peanut butter crumb layer in the pie shell. Let cool at room temperature for 15 minutes, then refrigerate for minimum 2 hours until fully set.
10 - Beat heavy cream, powdered sugar, and vanilla extract with electric mixer until stiff peaks form. Spread whipped cream evenly over chilled pie surface.
11 - Sprinkle remaining peanut butter crumbs generously over whipped cream topping before serving. Serve chilled.