Gather the ingredients.
Toast the chiles on a hot griddle or skillet over medium heat until browned, but not burned.
Remove the seeds and veins and place the chiles in a bowl; cover them with very hot water for 15 to 20 minutes.
When chiles have rehydrated, drain them.
Process chiles and vinegar in a blender to make a paste.
In a small bowl, mix together all of the rub ingredients. Rub the meat well with this mixture.
Coat the meat with half of the chile paste.
Cover loosely with plastic wrap and let it marinate overnight in the refrigerator.
Preheat oven to 350 F.
Pour the 1 cup of water into a Dutch oven or deep casserole dish. Add the coarsely chopped onion, bay leaves, diced garlic, and the remaining chile paste.
Place meat on a rack that sits just above the water mixture.
Place lid on the pot, making sure that it covers tightly, and bake for 4 hours.
Remove the meat from the Dutch oven.
Distribute the meat among six to eight bowls.
Serve with broth (as a soupy stew) or as a taco filling with corn tortillas.