Prepare the dried chiles by wiping them clean, removing stems and seeds, and briefly toasting in a dry skillet until aromatic; then soak in hot water until pliable, about 20 minutes.

Blend the softened chiles with diced tomatoes, half the onion, garlic, apple cider vinegar, cumin, oregano, smoked paprika, cinnamon, brown sugar (if using), 1 teaspoon kosher salt, and 1/2 teaspoon black pepper until very smooth, adding soaking liquid or water as needed to reach a sauce consistency.

Pat the beef dry, season with 1 teaspoon kosher salt and 1/2 teaspoon black pepper, then sear in 2 tablespoons vegetable oil in a Dutch oven until deeply browned on all sides; remove and set aside.

In the same pot, add the remaining onion to pick up fond, pour in the blended sauce, add the seared beef, beef broth, and bay leaves. Bring to a simmer, then cover and braise in a 300°F oven for 3–3 1/2 hours until the meat is fork-tender (or simmer on the stovetop or pressure-cook as directed).

Remove the meat and strain the braising liquid through a fine-mesh sieve, pressing solids to extract flavor. Skim fat if desired, then simmer the strained liquid until reduced by about one-third to concentrate into a flavorful consommé; season to taste.

Shred the beef with two forks, discard any large pieces of fat, and mix a few spoonfuls of the reduced consommé into the shredded meat to keep it moist and flavorful.

Assemble tacos: heat a skillet with a teaspoon of oil, place a corn tortilla in the pan, top with shredded cheese and a generous spoonful of meat, fold the tortilla or sandwich between two tortillas, and cook until the cheese melts and the tortilla crisps, about 1–2 minutes per side. Work in batches.

Transfer finished tacos to a platter, garnish with chopped cilantro and chopped white onion, and serve with warm consommé and lime wedges for dipping and finishing.