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 pie crust. Press gently to create an even layer.
03 - In a saucepan, whisk together granulated sugar, all-purpose flour, and salt until thoroughly blended. Gradually incorporate whole milk while whisking to prevent lumps.
04 - Place saucepan over medium heat. Cook mixture while whisking continuously until thickened and just beginning to bubble, approximately 4 to 5 minutes.
05 - Whisk egg yolks in a separate bowl. Gradually add small amount of hot milk mixture while whisking constantly to temper eggs and prevent curdling.
06 - Return tempered egg mixture to saucepan, whisking steadily. Continue cooking for 2 minutes until mixture achieves thick, glossy consistency.
07 - Remove from heat immediately. Stir in unsalted butter and vanilla extract 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 minimum 2 hours until fully set.
09 - Beat heavy whipping cream with powdered sugar and vanilla extract using electric mixer until stiff peaks form.
10 - Spread whipped cream topping over chilled pie surface. Sprinkle remaining peanut butter crumbs over top before slicing and serving.