Sukiyaki is a Japanese stir-fry that is traditionally prepared at the table in a special pan. Guests use chopsticks to serve themselves out of the pan or to cook the meat in the simmering broth, as with fondue. This recipe has been adapted so that it can be prepared quickly in your kitchen. It uses trefoil, a member of the parsley family, which has a long thin stem with many 3-pointed leaves. It has a light flavor somewhat similar to sorrel or celery. Trefoil can be found in some Asian markets but if it is not available, use 3 ounces of sorrel or spinach.