Step 1: Preheat your oven to 400°F (200°C). Arrange the husked tomatillos, poblano peppers, onion quarters, and unpeeled garlic cloves on a baking sheet. Drizzle with 1 tablespoon of olive oil and a pinch of salt. Roast for 20-25 minutes, or until the tomatillos are soft and slightly charred, the poblanos are blistered, and the garlic is tender.
Step 2: Once roasted, remove the baking sheet from the oven. Carefully transfer the poblanos to a bowl, cover with plastic wrap, and let steam for 10 minutes. This makes them easier to peel. Peel and deseed the poblanos, then roughly chop.
Step 3: Squeeze the softened garlic from its skin. In a blender, combine the roasted tomatillos (with any pan juices), roasted onion, peeled garlic, and chopped poblano peppers. Blend until smooth. Add a splash of chicken broth if needed to help it blend.
Step 4: Pat the chicken thighs dry with paper towels. Season generously with salt, pepper, cumin, oregano, and cayenne (if using).
Step 5: Heat the remaining 1 tablespoon of olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Sear the chicken thighs for 3-4 minutes per side, until nicely browned. You don't need to cook them through, just get a good sear. Remove the chicken from the pot and set aside.
Step 6: Pour the blended tomatillo mixture into the same pot. Bring to a simmer, scraping up any browned bits from the bottom of the pot. Cook for 5-7 minutes, stirring occasionally, allowing the sauce to thicken slightly and deepen in flavor. This step is crucial for rich tomatillo recipes.
Step 7: Return the seared chicken thighs to the pot. Pour in the chicken broth, ensuring the chicken is mostly submerged. Bring the stew to a gentle simmer, then reduce the heat to low, cover, and cook for 45-60 minutes, or until the chicken is fork-tender and easily shreds.
Step 8: Remove the chicken thighs from the pot and shred them using two forks. Return the shredded chicken to the stew.
Step 9: Stir in the chopped fresh cilantro and lime juice. Taste and adjust seasoning with salt and pepper as needed. If the stew is too thick, add a little more broth. If too thin, simmer uncovered for a few more minutes.
Step 10: Serve hot, garnished with extra cilantro, a dollop of sour cream or avocado slices, and alongside warm tortillas or rice. Enjoy your homemade hearty tomatillo stew!