Pipián Verde

Ingredients

• 1 onion (6 oz.), quartered
• 1/2 pound tomatillos, husked and rinsed
• 2 fresh jalapeño chilies (2 oz. total), stemmed
• 4 cloves garlic, peeled
• 2 romaine lettuce leaves
• 1 cup lightly packed fresh cilantro
• 1/4 cup radish leaves
• 1 2/3 cups (about 1/2 lb.) hulled, salted, and roasted pumpkin seeds
• 6 cups chicken broth
• 3/4 cup (about 1/4 lb.) unsalted, dry-roasted peanuts
• 1/3 cup Asian sesame seed
• 4 to 6 warm poached or baked boneless, skinless chicken breast halves (1 3/4 to 2 1/2 lb. total), sliced, or 2 pounds warm cooked firm-flesh fish, such as halibut or swordfish
• Cilantro sprigs
• Salt and pepper

Preparation

1. 1. In a 6- to 8-quart pan, combine onion, tomatillos, chilies, garlic, and 2 1/2 cups water.
2. 2. Bring to a boil over high heat; reduce heat, cover, and simmer until vegetables are tender when pierced, about 20 minutes. Drain.
3. 3. In a food processor or blender, smoothly purée vegetable mixture with romaine, cilantro, and radish leaves.
4. 4. Pour about half the purée into a bowl; set aside.
5. 5. Add 1 1/2 cups pumpkin seeds and 1/2 cup broth to purée in food processor; whirl until mixture is smooth. Pour into cooking pan.
6. 6. Pour purée from bowl back into food processor. Add peanuts, sesame seed, and 1/2 cup broth and whirl until smooth. Add to pan.
7. 7. Add 3 cups broth to pan. Bring to a simmer over medium heat. Cover and cook over low heat, stirring occasionally, until sauce thickens, about 30 minutes. Sauce will look curdled.
8. 8. In a food processor or blender, whirl about half the sauce and 1 cup broth until smooth. Pour into a fine strainer over a bowl, pressing sauce through with the back of a spoon; discard residue.
9. 9. Purée remaining sauce and 1 cup broth, and rub through strainer. (If making ahead, cover when cool and chill airtight up to 2 days.)
10. 10. Return sauce to pan and stir over medium heat until hot.
11. 11. Ladle about 3/4 cup sauce onto each dinner plate; lay chicken in sauce and garnish with cilantro sprigs and remaining pumpkin seeds. Accompany with remaining sauce and salt and pepper to add to taste.