8 ancho chilies, wiped clean 1/2 cup cider vinegar 2 small onions, chopped 5 cloves garlic, chopped 1 tablespoon ground cumin 1 cup chicken stock 1/2 cup orange juice 2 tablespoons brown sugar 2 tablespoons tomato paste 1 tablespoon flour 3 pounds pork, cut into bite size pieces salt and pepper
On a hot cast iron skillet, toast the anchos until they begin to dance on the skillet and bubble. Be sure to turn them often so they do not burn. Transfer them to a pot and add vinegar and water. Bring to a boil and then simmer for 20 minutes.
In the meantime, toss the onion, garlic, and chicken stock into the slow cooker, in a small bowl stir together the orange juice, brown sugar, tomato paste, and flour and add to the slow cooker.
After the anchos are sufficiently softened, transfer the chiles and 1 cup of the liquid to a blender. Blend until the chiles and liquid form a thick paste.
Stir the paste into the slow cooker. Add the pork and stir making sure all of the meat is covered in sauce. Cover and cook on low for 6 to 8 hours. Add salt and pepper to taste, and serve with warm tortillas and an assortment of your favorite fixings.