10 tomatillos (about 1 1/4 pounds)—husked, rinsed and quartered
1 lightly packed cup cilantro sprigs
1 serrano chile, quartered
1/2 medium white onion, chopped
2 garlic cloves, smashed
1 tablespoon vegetable oil
Salt and freshly ground pepper
In a blender, combine the tomatillos, cilantro, serrano, onion and garlic and puree until smooth. In a medium saucepan, heat the vegetable oil. Add the salsa, season with salt and pepper and bring to a boil. Simmer over moderate heat until reduced to 2 1/2 cups, about 10 minutes. Let cool.