Sauce for Fish
2 tablespoons butter 1½ cups milk, scalded 2 tablespoons flour cup liquid from fish 2 tablespoons lemon juice 1 egg yolk Melt butter, add flour, then heated milk gradually. Add liquid from fish and lemon juice just before removing from fire. Just before serving, beat sauce into yolk of egg. Serve hot. 1 tablespoon catsup may be added if desired.