01 - Mix creamy peanut butter and powdered sugar in a medium bowl using a fork until crumbly texture forms. Reserve for later use.
02 - Distribute half of the prepared peanut butter crumbs evenly across the bottom of the 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 constantly until smooth and no lumps remain.
05 - Place saucepan over medium heat. Cook while whisking continuously until mixture thickens and begins to boil, approximately 4-5 minutes.
06 - Whisk egg yolks in a separate bowl. Slowly incorporate a small amount of the hot milk mixture while whisking rapidly to warm the eggs gradually.
07 - Return tempered egg mixture to the saucepan. Cook for 2 additional minutes while whisking constantly until thick and glossy.
08 - Remove from heat. Stir in unsalted butter and vanilla extract until completely smooth and incorporated.
09 - Pour the warm filling over the peanut butter crumbs in the pie shell. Let cool at room temperature for 15 minutes.
10 - Refrigerate pie for minimum 2 hours until filling is completely set and firm.
11 - Beat heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form.
12 - Spread whipped cream evenly over the chilled pie surface. Sprinkle remaining peanut butter crumbs over top before serving.