Preheat your oven to 350°F (175°C).

Place the pre-made pie crust into your pie dish, pressing gently to fit.

In a mixing bowl, combine sugar, cornstarch, and salt.

In another bowl, whisk together milk, egg yolks, and vanilla extract until well combined.

Gradually add the wet mixture to the dry mixture, whisking continuously.

Transfer the mixture to a saucepan over medium heat, stirring constantly until it thickens.

Remove from heat, stir in the butter, and pour the filling into the prepared pie crust.

Bake the pie in the preheated oven for 30 to 45 minutes.

Let the pie cool completely before slicing.