Béchamel Sauce (one of the five mother sauces) 

Ingredients: Butter, flour and milk. 

Preparation: This basic French white sauce is made by stirring milk into a butter-flour roux. The thickness of the sauce depends on the proportion of flour and butter to milk. The proportions for a thin sauce would be 1 tablespoon each of butter and flour per 1 cup of milk; a medium sauce would use 2 tablespoons each of butter and flour; a thick sauce, 3 tablespoons each.