As has been pointed out, the giblets–that is, the liver, heart, and gizzard of all kinds of fowl–are used in gravy making and as an ingredient for stuffing. When poultry is stewed, as in making stewed CHICKEN, it is not uncommon to cook the giblets with the pieces of CHICKEN. The gizzard and heart especially require long, slow cooking to make them tender enough to be eaten. Therefore, when poultry is broiled, fried, or roasted, some other cookery method must be resorted to, as these processes are too rigid for the preparation of giblets. In such cases, the best plan is to cook them in water until they are tender and then sauté them in butter. When cooked in this way, they may be served with the poultry, for to many persons they are very palatable.
Woman’s Institute Library of Cookery, Vol. 3
Volume 3: Soup; Meat; Poultry and Game; Fish and Shell Fish (Year 1928)