Grandma's Butterscotch Pie Recipe

In top of double boiler combine brown sugar cornstarch salt and milk. Cook stirring constantly until mixture starts to thicken about 20 minutes.

Whisk in egg yolks; continue to cook and stir until filling is thickened.

While pudding mixture is cooking preheat the oven to 400 degrees F (200 degrees C).

Remove filling from heat and stir in butter and vanilla.

Pour filling into prepared pie crust. Bake in preheated oven until top begins to brown about 5 minutes.