1 1/2 pounds beef chuck roast
2 tablespoons tomato paste
1 teaspoon chipotle powder
1 teaspoon ground cumin
1/2 teaspoon dried oregano
1/2 teaspoon salt
4 cloves garlic, peeled
2 large seedless oranges, quartered
12 taco shells or corn tortillas
3 cups shredded lettuce
3 medium tomatoes, chopped
1 1/2 cups shredded Monterey Jack cheese
Place the beef in a slow cooker. Stir together the tomato paste, chipotle, cumin, oregano and salt in a small bowl, then rub the mixture over the beef. Place garlic cloves and oranges on top of the meat and cover the pot. Turn temperature to high and cook for 4 hours, or on low for 7 to 8 hours. When the meat shreds when pressed with a fork, turn off the cooker and take out the insert to cool. Use tongs to transfer the meat to a bowl to cool, and shred the beef.
Place a strainer over a small pot and strain the liquids from the cooker into the pot. Squeeze the oranges over the strainer. Bring the juices to a boil and cook for about 10 minutes, until reduced to a syrupy consistency. Pour over the shredded beef and toss to coat. Taste for seasoning; add salt or more chipotle, if desired. Serve with taco shells or warm corn tortillas, lettuce, chopped tomato and shredded cheese.
Tips: Pair these tacos with tortilla chips and homemade guacamole or your favorite salsa. The meat can also be folded into larger tortillas with leftover cooked rice to make tasty burritos.