Veal and lamb kidneys are the most popular, especially in the more upscale restaurants. They are usually prepared by sautéing and broiling. Beef kidneys are tougher and more strongly flavored. They are often cooked by braising and served in specialty items, like steak and kidney pie. Pork livers are not often used.
Veal kidneys weigh 8–12 oz (240–360 g) each. Lamb kidneys are very small, 1½–3 oz (45–90 g) each. If you purchase whole lamb or veal carcasses, you will find a pair of kidneys inside the cavity, attached to the small of the back in the region of the tenderloin and surrounded by a heavy layer of fat or suet.