- 1.
**Prepare the Barbacoa:** Rehydrate the dried chiles by soaking them in hot water for 30 minutes. Drain the chiles and transfer them to a blender along with onion, garlic, cumin, oregano, apple cider vinegar, and beef broth. Blend until smooth.
- 2.
Season the lamb shoulder generously with salt and pepper. Place the lamb in a Dutch oven or slow cooker. Pour the chile mixture over the lamb, ensuring it's coated evenly.
- 3.
**Slow Cook:** If using a Dutch oven, bake in a preheated oven at 325°F (160°C) for 3-4 hours, or until the lamb is incredibly tender and easily shreds with a fork. If using a slow cooker, cook on low for 6-8 hours or on high for 3-4 hours.
- 4.
Once the lamb is cooked, remove it from the pot and shred it using two forks. Strain the cooking liquid, discarding the solids. Return the shredded lamb to the strained cooking liquid to keep it moist.
- 5.
**Prepare the Masa:** In a large mixing bowl, combine the masa harina, lard (or vegetable shortening), and baking powder. Gradually add the warm chicken broth, mixing until a soft, dough-like consistency is achieved. The masa should be moist but not sticky. Add more broth if needed.
- 6.
**Assemble the Tamales:** Soak corn husks in warm water for at least 30 minutes to soften them. If using parchment paper, cut into 6 inch squares. Spread a thin layer of masa (about 1/4 cup) onto each corn husk or piece of parchment paper. Top with a generous spoonful of shredded lamb barbacoa.
- 7.
Fold the sides of the corn husk or parchment paper over the filling, creating a sealed packet. If using corn husks, fold the bottom up. Secure with kitchen twine, if needed.
- 8.
**Steam the Tamales:** Fill a large pot with a few inches of water. Place a steamer basket inside the pot, ensuring the water level is below the basket. Arrange the tamales upright in the steamer basket, leaving some space between them.
- 9.
Cover the pot with a tight-fitting lid and steam the tamales for 45-60 minutes, or until the masa is firm to the touch and pulls away easily from the corn husk or parchment paper. Check the water level periodically and add more water if needed.
- 10.
**Prepare Pickled Red Onions:** While the tamales are steaming, prepare the pickled red onions. In a medium bowl, combine the sliced red onion, lime juice, apple cider vinegar, salt, and sugar. Mix well and let sit for at least 30 minutes, or up to a few hours, to allow the onions to soften and pickle.
- 11.
**Serve:** Carefully remove the tamales from the steamer. Unwrap each tamale and top with the pickled red onions. Serve immediately and enjoy!