Mustard Sauce

Two tablespoons of butter, 1½ tablespoons of flour, 1 cup of scalded milk, ¼ teaspoon of salt, ½ teaspoon of mustard, ½ teaspoon of vinegar.

Blend the butter and flour in a saucepan and pour on the milk little by little, then add the salt, mustard, and vinegar.

A spoonful of mixed capers is sometimes added.