From: Chef Roberto Santibanez, La Botaneria and Fonda, NYC. Yield: 4 to 6 servings.
3 to 3½ lb. whole chicken, cut into serving pieces
6 to 8 cups of water
½ tsp. fine salt or 1 tsp. coarse salt
1 bay leaf
½ tsp. Mexican oregano
2 garlic cloves
9 oz. tomatillos, husked, rinsed
1 to 2 serrano chiles, stemmed
1/3 cup white onion, chopped
1 cup cocktail peanuts, roasted, salted
½ tsp. ground cumin
1 tsp. fine salt or 2 tsp. coarse salt
1 garlic clove, peeled
½ cup cilantro, chopped, divided
3 to 4 cups chicken stock, divided
2 Tbsp. vegetable oil
For chicken: Add chicken to a 5 to 6 qt. pot with enough water to cover and bring to a boil, skimming surface as necessary. Add the salt and aromatics and simmer until the chicken is cooked through, about 30 minutes. Transfer chicken to a plate and remove the skin. Strain stock.
While chicken is cooking, add tomatillos, serrano chiles and onion to a small saucepan with water to cover and bring it to a simmer. Lower heat and simmer gently, turning occasionally until tomatillos have turned a khaki green color and are tender but still intact (about 15 minutes). Let stand in pan 10 to 15 minutes to finish cooking insides of tomatillos. With a slotted spoon, transfer cooked tomatillos, serranos and onion to a blender, then add peanuts, cumin, salt, garlic, ¼ cup of cilantro and 2 cups chicken stock. Blend until smooth, about 3 minutes.
Heat oil in a 4 to 5 qt. heavy pot (with enough room to add the chicken later) over medium heat, then add blended mixture and bring to a simmer.
Simmer the sauce over low heat, uncovered, stirring frequently and adding more broth as necessary to maintain a velvety coating texture, until sauce starts making small pools of oil around the bubbles (about 30 minutes).
Blend 1 cup of sauce with remaining ¼ cup cilantro until speckled, then return to sauce and season with salt to taste. Reheat chicken in sauce to serve.