Directions

1. Gather the ingredients.
2. In a large enameled cast-iron casserole, bring the chicken stock and water to a boil.
3. Add the chicken breasts skin side down, cover, and simmer over very low heat until they're tender and cooked through, about 25 minutes.
4. Skim and discard any fat from the cooking liquid and set the liquid aside.
5. Transfer the chicken breasts to a cutting board or plate and, once cool enough to handle, shred the meat; discard the bones and skin.
6. In a blender, combine the halved tomatillos with the quartered onion, poblanos and jalapeños, smashed garlic, chopped cilantro, and oregano. Pulse until coarsely chopped, scraping down the sides.
7. With the machine on, add 1 cup of the cooking liquid and puree until smooth. Season the tomatillo puree with salt and pepper.
8. In a large, deep skillet, heat the vegetable oil until shimmering. Add the tomatillo puree and cook over moderate heat, stirring occasionally, until the sauce turns a deep green, about 12 minutes.
9. Pour the green sauce into the cooking liquid in the casserole. Add the hominy and bring to a simmer over moderate heat. Add the shredded chicken to the stew, season with salt and pepper, and cook just until heated through.