1Heat oven to 475°F. Line 15x10x1-inch pan with foil. Place tomatillos in single layer on one end of pan; place poblano chiles and onion on other end. Drizzle oil over vegetables.
2Roast uncovered 15 minutes or until vegetables are browned and tender.
3Place poblano chiles in resealable food-storage plastic bag; seal bag. Let stand 15 minutes. Peel poblano chiles; discard seeds and membranes. In food processor, place poblano chiles, tomatillos, onion and remaining ingredients. Cover; process until smooth. Spoon into serving bowl. Store tightly covered in refrigerator.