Chef John'S White Sauce - cooking recipe

Ingredients

1/2 cup butter
1/2 cup flour
1 quart milk
4 sprigs fresh thyme, chopped
1/8 teaspoon freshly grated nutmeg
salt
1 pinch cayenne pepper, or more to taste

Preparation

Melt butter in a saucepan over low heat. Stir in flour and cook for about 5 minutes.
Stir in 1 cup cold milk, about 1 minute. Stir in second cup of milk for an additional minute.
Stir in remaining 2 cups of milk, cayenne pepper, salt, thyme, and nutmeg; bring to a simmer over low heat until sauce begins to thicken, about 10 minutes.