Preheat the broiler with the rack adjusted at the highest setting. Cover a baking sheet with foil and top with the fresh Anaheim chile, the onion quarter, and the 2 unpeeled garlic cloves. Broil for about 10 to 12 minutes, flipping the vegetables over halfway through, until completely charred on the outside and soft on the inside. The garlic will be done before the other ingredients, usually halfway through, and should be removed from the baking sheet when you see that it is charred and softened. Alternatively, you can roast the vegetables on a comal over medium heat, flipping them over every 4 to 5 minutes, until charred.
Place the chile in a plastic bag and let it sweat for 5 to 10 minutes. Remove the skin, stem and seeds from the chile and peel the garlic. Cut the chile into pieces and place it in a blender along with the charred onion, the peeled roasted garlic cloves and 10 sprigs of fresh cilantro. Add the cup of strained chicken broth that you set aside, and puree until completely smooth. Pour back into the soup pot or casserole with the chicken and remaining broth.
Remove the onion from the pinto beans and stir the beans into the soup pot, along with 1 cup of their broth (or more, to taste). If using canned beans, rinse and add to the soup pot. Discard the halved head of garlic you added to the hominy and add the cooked hominy along with 1 cup of its liquid (or more to taste) to the soup pot. If using canned hominy, drain, rinse, and add to the pot.
Return the pot to medium heat, bring to a simmer and simmer, partially covered, for 15 to 20 minutes. You will know it’s ready when the seasoning sauce pools on the surface into tiny dark green puddles that are a darker green than the rest of the soup. Taste and adjust salt.
Serve and let everyone garnish with chopped white onion, cilantro, chiltepin chiles and a squeeze of fresh lime.