When cooked at a boil for too long, corned beef is likely to turn out tough and chewy, rather than soft and tender. Do this instead: Regardless of the cooking method, corned beef is best cooked over low heat.
In the U.S., corned beef is made from beef brisket. You might have seen it at Jewish delis, and that's because the brisket is a traditionally kosher cut of meat that's cured to tenderize it.