These tacos are common fare available in West-coast, Mexican-American markets. Sometimes, they are made from cow innards: brain, tongue, stomach, etc.
2 lbs chuck roast
1 clove garlic
water and/or beer
1/2 cup tomato purée
1 large onion
1 small bell pepper (optional)
2 cloves garlic
1 Tsp ground cumin
1 Tbl ground chile d'arbol powder
lard, bacon grease or olive oil
cheddar, colby or jack cheese
Remove the excess moisture from the roast with paper towels. Sear it in a Dutch oven, browning all of its sides. Degrease the pan. Season the meat. Cover with water. Add 1 clove of garlic. Bring the liquid to a boil then simmer slowly, covered, until tender - about 3 hours.
Slice the onion into thick rings. Crush the garlic. Remove the beef from the pan. Discard the garlic clove. Pour off the poaching liquid. Reserve this liquid. Shred the roast with two forks into long strands. Heat the lard in the pan. Saute the onion and garlic until soft. Return the beef to the pan. Add the tomato purée cumin and chili pepper. Barely cover with the reserved poaching liquid. Season with salt and pepper. Simmer slowly, uncovered, for 20 minutes.
Construct tacos with pan softened tortillas by adding generous portions of the beef mixture, followed by the cheese and lettuce. Top with sour cream and salsa - if desired.
Before adding the poaching liquid to the beef mixture, skim the fat from it. Excess fat will produce greasy tacos. This dish improves by age. Allow the flavors to mature by refrigerating overnight. These tacos can be made from any meat. A 2 lb pork butt roast seared, poached and shredded will make for tender porky tacos.