In its simplest form, fond lié, or jus lié, is a brown stock thickened lightly with arrowroot or cornstarch. Its quality can be improved, however, by applying the technique used for making espagnole—that is, reduce brown stock with browned mirepoix and tomato purée or tomato paste, and then thicken with a starch slurry and strain. You can use the same ratio of stock to mirepoix as for espagnole.
