01 - Combine creamy peanut butter and powdered sugar in a medium bowl, mixing with 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, flour, and salt in a saucepan. Gradually incorporate milk while whisking until smooth and no lumps remain.
04 - Place saucepan over medium heat, whisking constantly until mixture thickens and begins to bubble. Continue cooking for 4-5 minutes to fully activate thickening agents.
05 - Whisk egg yolks in a separate bowl. Gradually stream in small amount of hot milk mixture while whisking continuously to gently warm yolks without cooking them.
06 - Return tempered yolk mixture to saucepan, whisking constantly. Cook for 2 additional minutes until filling achieves thick, glossy consistency.
07 - Remove from heat source. Stir in unsalted butter and vanilla extract until completely smooth and fully incorporated.
08 - Pour warm filling over peanut butter crumb layer in crust. Allow to 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 using electric mixer until stiff peaks form and mixture holds shape.
10 - Spread whipped cream evenly over chilled pie surface. Sprinkle reserved peanut butter crumbs over top before slicing and serving.