Preheat your oven to 375°F (190°C) and fit the 9-inch pre-baked pie crust into a pie dish. Crimp the edges and line with parchment paper, filling it with pie weights or dried beans. Bake for 12-15 minutes until golden brown. Allow to cool completely.

In a mixing bowl, combine ½ cup creamy peanut butter with ½ cup powdered sugar until the mixture resembles crumbs. Set aside.

In a medium saucepan, whisk together 3 cups of whole milk, ¾ cup granulated sugar, ¼ cup cornstarch, and ¼ teaspoon salt over medium heat, stirring constantly until it thickens and bubbles (about 6-8 minutes).

In a separate bowl, whisk 3 large egg yolks and slowly add hot milk mixture, whisking continuously. Return to saucepan and cook for an additional 2-3 minutes until thickened.

Remove from heat and stir in ½ cup creamy peanut butter and 1 teaspoon pure vanilla extract until smooth.

Layer half of the peanut butter crumbles in the cooled pie crust, pour custard filling over, and chill in the refrigerator for at least 4 hours or overnight.

Beat 1 cup heavy whipping cream with 2 tablespoons powdered sugar until soft peaks form, which takes about 3-5 minutes.

Spread the whipped cream over the chilled pie, garnish with remaining peanut butter crumbles, slice, and serve.