Pan-Roasted Güero Chiles with Blackened Onions

Fresh chiles are so basic to Mexican cooking that it’s easy to overlook them as a treat in their own right. All chiles do not taste alike; pale yellow güero chiles (the name means “blond” and is often applied to Americans or light-haired Mexicans) have a pleasantly assertive flavor. The simple technique of pan-roasting them brings out their fruitiness and makes for a delicious nibble or side dish. A squeeze of lemon juice adds sweetness, while soy sauce subtly adds color and saltiness (soy