Organ meats like beef kidney aren’t popular in the United States and Europe, but they can be a tender and flavorful cut if prepared correctly. Unlike lamb or veal kidneys, beef kidneys are large and tough and require long braising over low, moist heat to become soft. Add chopped vegetables to the braising liquid along with the kidneys to make a stew that can be spooned over rice or mashed potatoes, or serve cooked beef kidneys with crusty whole-wheat bread to mop up the sauce.