Fried Serrano Chile Salsa
- 1 3/4-inch-thick slice from medium-size white onion
- 1/2 teaspoon coarse kosher salt
Heat oil in medium saucepan over medium-high heat. Fry chiles until blistered, about 3 minutes. Remove chiles from oil. Cool chiles and chile oil completely.
Line large skillet with foil; heat over medium heat. Add onion and cook until softened and blackened in spots, about 5 minutes per side. Cool.
Cut stems off chiles. Combine chiles, onion, garlic, salt, and 2 tablespoons chile oil in blender; chop finely. With blender running, slowly drizzle in remaining chile oil and blend until thick. DO AHEAD: Can be made 1 day ahead; cover and chill.