You must season your mousseline forcemeat with enough salt and other flavorings to give it a good taste but not so heavily as to mask the basic flavor of the seafood or meat. Some flavorings, such as saffron and tomato paste, add color as well as flavor. Whatever seasonings and flavorings are used, they must not mar the smooth texture of the mousseline. Spices, herbs, and aromatics must be minced extremely fine. Vegetables must be puréed and then reduced (moisture cooked off) so as not to dilute the forcemeat.