I have used this Basic White Sauce recipe for many years (about 30) and I learned how to make it from my Grandmother, so it's been our family for a long time. It can be used as a base for lots of dishes.
1 Tablespoon butter
1 Tablespoon flour
½ teaspoon sea salt
1 cup milk
In a small saucepan over medium heat, melt butter.
Add flour and stir until the butter and flour are well combined.
Pour in milk, stirring constantly as it thickens.
Add more milk depending on desired consistency.