From Cook's Illustrated. It's similar to their Cuban Style Shredded Beef recipe which I love. Here are their notes:
Traditional carnitas, Mexico’s version of pulled pork, is fried in gallons of lard or oil. The results are tasty, but who wants to deal with all that hot fat? We wanted to create restaurant-style carnitas—tender chunks of lightly crisped, caramelized pork, subtly accented with oregano and citrus—without the hassle of frying. Our initial recipe for carnitas started by simmering the meat (taste tests proved boneless pork butt had the best flavor) in a seasoned broth in the oven and then sautéing it in some of the rendered fat. The flavor was OK, but too much of the pork flavor went down the drain when we discarded the cooking liquid. So we kept the liquid and reduced it on the stovetop (after the meat had been removed) until it developed the consistency of a thick, syrupy glaze that was perfect for coating the meat. Broiled on a rack set over a baking sheet, the glazed meat developed a wonderfully rich flavor and the rack allowed the excess fat to drip off. We emulated the flavor of the Mexican sour oranges used in authentic carnitas with a mixture of fresh lime and orange juices. Bay leaves and oregano provided aromatic notes, and cumin brought an earthy dimension that complemented the other flavors. Like the best barbecue, Mexico’s version of pulled pork offers fall-apart chunks of crisp meat—but without the hassle of tending a fire.
1(3 1/2-to 4-pound) boneless pork butt, fat cap trimmed to 1/8 inch thick, cut into 2-inch chunks
Salt and ground black pepper
1 teaspoon ground cumin
1 small onion, peeled and halved
2 bay leaves
1 teaspoon dried oregano
2 tablespoons juice from 1 lime
2 cups water
1 medium orange, halved
Tortillas and Garnishes
18 (6-inch) corn tortillas, warmed
Minced white or red onion
Fresh cilantro leaves
Thinly sliced radishes
1. Adjust oven rack to lower-middle position and heat oven to 300 degrees. Combine pork, 1 teaspoon salt, 1/2 teaspoon pepper, cumin, onion, bay leaves, oregano, lime juice, and water in large Dutch oven (liquid should just barely cover meat). Juice orange into medium bowl and remove any seeds (you should have about 1/3 cup juice). Add juice and spent orange halves to pot. Bring mixture to simmer over medium-high heat, stirring occasionally. Cover pot and transfer to oven; cook until meat is soft and falls apart when prodded with fork, about 2 hours, flipping pieces of meat once during cooking.
2. Remove pot from oven and turn oven to broil. Using slotted spoon, transfer pork to bowl; remove orange halves, onion, and bay leaves from cooking liquid and discard (do not skim fat from liquid). Place pot over high heat (use caution, as handles will be very hot) and simmer liquid, stirring frequently, until thick and syrupy (heatsafe spatula should leave wide trail when dragged through glaze), 8 to 12 minutes. You should have about 1 cup reduced liquid.
3. Using 2 forks, pull each piece of pork in half. Fold in reduced liquid; season with salt and pepper to taste. Spread pork in even layer on wire rack set inside rimmed baking sheet or on broiler pan (meat should cover almost entire surface of rack or broiler pan). Place baking sheet on lower-middle rack and broil until top of meat is well browned (but not charred) and edges are slightly crisp, 5 to 8 minutes. Using wide metal spatula, flip pieces of meat and continue to broil until top is well browned and edges are slightly crisp, 5 to 8 minutes longer. Serve immediately with warm tortillas and garnishes.