Start by baking your crust at 375°F (190°C) until golden brown. If it’s store-bought, just blind bake it for about 12–15 minutes. Let it cool completely before adding the filling. A cooled crust ensures the creamy filling sets properly.
In a saucepan, whisk together sugar, cornstarch, and salt. Slowly pour in the milk so you don’t get lumps. Cook over medium heat, stirring constantly, until it thickens. Temper the egg yolks by whisking in some of the hot mixture, then return them to the saucepan. Cook a few more minutes, then stir in peanut butter and vanilla until smooth.
Pour the filling into the cooled crust and smooth it out with a spatula. Cover directly with plastic wrap so it touches the filling—this prevents a skin from forming. Refrigerate for at least 4 hours, or until firm. The longer it chills, the better the texture.
Whip the heavy cream, powdered sugar, and vanilla until stiff peaks form. Spread generously over the chilled pie, or pipe it on if you want a fancier look. Whipped cream makes this pie extra light and balanced.
Sprinkle chopped peanuts, drizzle peanut butter, or shave some chocolate on top. Slice and serve chilled. Every bite is creamy, nutty, and absolutely delicious.