https://www.mysupersave.com/Recipes/Detail/4487/White_Sauce
Yield: 2 cups sauce
Melt butter in 1 1/2 qt. saucepan over low heat.  Stir in flour, salt and pepper.  Cook over medium heat, stirring constantly, until mixture is smooth and bubbly;  remove from heat.  
Gradually stir in milk.  Heat sauce to boiling, stirring constantly.  Boil and stir 1 minute.  
Please note that some ingredients and brands may not be available in every store.
https://www.mysupersave.com/Recipes/Detail/4487/White_Sauce