Lamb is the meat of young domestic sheep, before it grows its first pair of permanent teeth around age 2 and is classified as mutton. Lamb is used in Europe and the states for some holiday meals, but it and mutton are most used in cooking in the Arab world and areas influenced by it, such as North Africa, and its also common in Pakistan, Central Asian countries, and North Indian Moghul cuisine. Being the smallest of the common meat animals, lamb allows the luxury of being able to consume whole shoulders or legs in a single sitting. The lamb often appears in the coats of arms of butchers' guild, particularly in Paris.
When choosing lamb, one should look for the leanest piece possible, avoiding meat with fat that looks brittle and crumbly or discolored. Also, a blue tinge in the rib bones can indicate the meat came from a young animal. Lamb is graded Prime, Choice, and Good, with the majority of it being Choice, and less than 10% being graded Prime.
The location the sheep were raised can also affect the flavor, with mountain lamb being a touch gamier. Some of the most delicious lamb is said to come from sheep that have grazed on salt marshes, such as the pre-sale (pre-salted) lamb of France's Atlantic coast. The lamb sold in the United States is produced in every state of the union, with flocks concentrated in the West, especially Colorado and California. Australian and New Zealand lamb are also widely available in the U.S., either frozen or deep-chilled. The individual cuts of American lamb tend to be the larger of the three, with more meat in proportion to the bone, while New Zealand lamb tend to be the smallest but not necessarily the mildest or most tender.
In French culinary practices, the three types of lamb recognized are Milk Lambs, which have pale, tender, and flavorless flesh from being fed only on their mother's milk. Laiton are slaughtered between 70-150 days and provide about 70% of the lamb meat on the French market, and have dark pink meat, white fat, and are also very tender. Grazing lambs, known as Broutart, are killed at 6-9 months, and tend to be preferred by gourmets for their firmer flesh and stronger flavor. Its diet results in fat which has lost its whiteness, giving rise to its French name of agneau gris (grey lamb). In England and the United States, milk lambs are known as suckling, milk-fed, and baby lamb, while animals over 1 year old are called "Yearling" lamb. Yearlings are considered to be the most flavorful of all the domesticated meats, and the assortment of muscle groups in its flesh provide a variety of tastes and textures. Also, there are athletic lamb from craggy hillsides with no pastures to speak of that are known as Kids, which produce meat notable for flavor, though they can be tough or dry. Kids are often preferred over lamb in the areas they are plentiful, including Corsica, Sardinia, and Saudi Arabia. Kid and lamb are interchangeable in recipes, though kid is milder in taste and often requires plenty of flavoring.
Suckling lambs are often cooked whole or cut into quarters, but jointed down, the American cuts of lamb are the Shoulder, Neck Slice, Rib, Loin, Loin Chop, Leg, Hind Shank, Breast, Riblets, and Fore Shank. The French cuts are the Cullet (small animals) or Collier (large animals), Carre de Cotes Decouvertes, Carre de Cotes Premieres: Cotes Premieres & Cotes Secondes, Gigot, Haut de Cotelletes, Poitrine, Filet, Selle de Gigot, and Gigot Entier (with Selle).
Leg of lamb is often roasted on the bone, but also appears boned, and is then rolled or butterflied. Lamb neck, shoulder, breast, and saddle are also used for roasting, while various cuts are additionally diced for braising, stewing, and grilling, and minced for use in stuffing, meatballs, and other dishes.
Large cuts of lamb are covered with a white, papery membrane called the fell, which must be removed before cooking. The fell is indigestible, and also prevents seasonings and even heat from penetrating the meat.
Most gourmets consider lamb to be at its best when cooked rare, though it is also appreciated cooked to medium and well done, as its juice and flavor carries through the cooking process.
While used as a foundation of a number of classic dishes, lamb does not carry the importance of beef in haute cuisine. Its fat has a distinctive flavor which is generally not liked in the western world, though both lamb stock and fat are used heavily in some areas of the world like the Middle East and Central Asia.
Fat-tailed sheep of lamb age or older are often roasted with the tail intact, curved over the body to display it and to help baste the meat, while smaller pieces of lamb and mutton are often used to make skewered kebabs.
With its fatty meat, most cuisines call for an acid ingredient or sauce to "cut" the flavor, such as a mint sauce (England), wine or wine vinegar basting (Spain), egg yolks & lemon juice (Greece), or citrus fruit (N. Africa). Also used are strongly-flavored seasonings, like thyme, rosemary, and oregano (France), paprika (Spain & Portugal), rosemary or anchovy and garlic (Italy), and tarragon (Romania, Hungary), or fat-absorbing starches like potatoes or rice. Indian dishes with moist lamb are usually highly-spiced with ingredients including root ginger, fresh chilies, and garlic, while asafoetida is used in place of garlic in Kashmir. Cinnamon, cloves, cumin, coriander seeds, and other spices are often used to flavor stews of lamb and potatoes or turnips. Spiced rice dishes in the Pilaf category often accompany lamb in the Middle East, Asia, and Europe, while couscous is the common base for lamb and mutton dishes in North Africa.
References:
Larousse Gastronomique; 2001; Pages 441 - 442
Oxford Companion to Food; 1999; Page 663-665
How to Cook Everything; 1998; Pages 477 - 488
Barnes & Noble Essentials of Cooking; 2001; Pages 56 - 58
The Cooking Enthusiast; 2000 ; Page 146
Joy of Cooking; 1997; Pages 708 - 709