Instructions:
- Poach the Chicken: Place chicken, 6 cups broth, onion quarters, 2 smashed garlic cloves, and 1 tsp salt in the Dutch oven. Bring to a boil, then reduce heat, cover, and simmer until cooked through (about 18-20 minutes).
- Shred the Chicken: Remove chicken; reserve 1/4 cup of the cooking broth. Once cool enough to handle, shred the chicken coarsely using two forks or your fingers. Set aside.
- Roast Aromatics (Optional but Recommended): Lightly char the tomato halves and whole garlic cloves either under the broiler or in a dry, hot pan until slightly blackened.
- Sauté Onions: Heat 1 tbsp oil in the large skillet over medium heat. Add the sliced onion and sauté gently for 8-10 minutes until soft and translucent.
- Blend the Sauce Base: Transfer the sautéed onions, roasted tomatoes, roasted garlic, chipotle peppers, adobo sauce, oregano, and cumin to a blender. Add the reserved 1/4 cup of chicken broth. Blend until completely smooth.
- Simmer the Tinga: Pour the blended sauce mixture over the sautéed onions in the skillet. Bring to a gentle simmer and cook for 5-7 minutes, stirring occasionally, allowing the sauce to thicken slightly.
- Combine and Finish: Add the shredded chicken to the simmering sauce. Stir well to ensure every strand is coated. Reduce heat to low and let it cook, uncovered, for another 5-10 minutes so the chicken fully absorbs the sauce.
- Serve: Check seasoning one last time and serve hot.