Ree Drummond offers a recipe for spicy Dr. Pepper shredded pork at ThePioneerWoman.com. The recipe calls for onion, pork shoulder, chipotle peppers, Dr. Pepper and brown sugar and cooks in about six hours.
Preheat an oven to 300 degrees Fahrenheit. Peel a whole large onion, and quarter it. Lay the onion wedges along the bottom of a large Dutch oven. Season a whole 5 to 7-pound pork shoulder with a liberal amount of salt and freshly ground black pepper, and set it atop the onions in the pot. Pour an 11-ounce can of chipotle peppers in adobo sauce over the pork shoulder. Pour in 2 cans of Dr. Pepper soda, then stir in 2 tablespoons of brown sugar.
Cover the pot, and place it in the oven. Cook at 300 degrees Fahrenheit for at least six hours. Turn the roast two or three times during the cooking process. The meat is ready when it falls apart when prodded with two forks. Return the shoulder to the oven for an extra hour if it does not fall apart.
Once the pork is fall-apart tender, remove it to a cutting board, and use two forks to shred the meat. Discard large pieces of fat, and strain any fat off the top of the cooking liquid. Put the shredded pork back into the cooking liquid and keep warm. Serve on warm flour tortillas with shredded lettuce, diced tomatoes, grated cheese, avocado slices and salsa.