Pork carnitas is traditionally made using the heavily marbled, rich 'boston butt' or 'picnic ham' cuts of pork. Contrary to their misleading names, these are neither rump or ham areas, but rather the upper and lower sections of the front shoulder of the hog. The 6–16 lb (3–7 kg) sections are usually cut down to a workable (6–10 lb) size and seasoned heavily before slow braising or slow roasting, generally in the range of 160 to 180 °F for 8 to 12 hours. At this stage the collagen in the meat has broken down sufficiently to allow it to be pulled apart by hand or fork or chopped with a cleaver.
Having been dismantled, some of the rendered liquid is added back to the pork. Prior to serving, the pork is placed in fairly shallow pans to maximize surface area, then roasted at high (375 to 425 °F or 190 to 220 °C) heat for a few minutes to produce the famous alternating texture of succulent softness and caramelized crispness.
The carnitas of Sahuayo, Michoacán are internationally well-known; they’re very flavorful and are served accompanied with chopped coriander (cilantro) and diced onion, salsa, guacamole, tortillas (handmade), refried beans (frijoles refritos), lemon and radishes; the different parts as the carnitas are ordered (more requested) to the chef are aldilla, nana, crop (buche), rib (costilla), cuerito (little skin leather), maciza (solid part), kidney, etc. and are served hot.
Traditional carnitas. Given today's climate for more low-fat, healthier foods, alternative methods like braising and roasting have become popular. These non-traditional methods tend to produce a less savory result. The traditional way to cook carnitas is in a copper pot which disperses the heat evenly (you may use any thick bottomed pot to get the same result). You begin by using enough lard to cover all the meat you will cook. Once the lard has melted, add pork and flavorings (usually salt, oregano, marjoram, thyme, bay leaf, crushed garlic cloves), then add milk. The trick to traditional carnitas is to simmer the meat until tender over a very low heat. Once the meat is tender, the heat is turned up, the milk will evaporate, and the outside of the pork will begin to get crisp. Once this is done, the carnitas can be cooled and shredded.
Another method of cooking carnitas is by using a citrus juice of some sort in place of milk; usually lime. This is a method observed by many Mexican Chicanos. Cola flavored soda is also used as substitute for milk.