- 3 ounces dried whole New Mexico chiles
- 4 cups boiling water
- 2 tablespoons fine dry bread crumbs
- 1 1/2 tablespoons vegetable oil
- 1 garlic clove, minced
- 1 teaspoon dried oregano, crumbled
- 1 tablespoon cider vinegar
- 2 teaspoons salt
- 3 large onions, chopped (4 cups)
- 3 tablespoons olive oil
- 12 (5-inch) white or yellow corn tortillas
- 3/4 pound white sharp Cheddar, coarsely grated (5 cups)
- 1 (6-ounce) can pitted black olives, sliced
- Rinse chiles and split open, discarding stems, seeds, and ribs. Heat a dry well-seasoned cast-iron skillet over moderate heat, then toast chiles in batches, turning them, about 30 seconds total. Transfer to a heatproof bowl and pour boiling water over them. Cover bowl and soak chiles, stirring occasionally, until softened, about 15 minutes.
- Reserve one fourth of soaking liquid, then purée chiles with remaining liquid in a blender until smooth (use caution when blending hot liquids). Pour puréethrough a fine sieve into a bowl, pressing on solids. Whisk in reserved soaking liquid.
- Toast bread crumbs in oil in a 2-quart heavy saucepan over moderate heat, stirring constantly, until pale golden, about 1 minute. Add garlic and oregano and cook, stirring, until fragrant, about 1 minute. Stir in chile purée, vinegar, and salt and simmer, stirring occasionally, until slightly thickened, about 25 minutes.
- Preheat oven to 350°F.
- Cook onions in oil in a 12-inch heavy skillet over moderately low heat, stirring occasionally, until softened, about 20 minutes.
- Spoon half of chile sauce evenly over bottom of a lightly oiled 13- by 9-inch (3-quart) baking dish, then cover with 4 tortillas, overlapping slightly. Sprinkle tortillas evenly with one third of cheese, then half of onions and olives. Repeat layering with another 4 tortillas, another third of cheese, and remaining onions and olives. Top with remaining 4 tortillas, sauce, and cheese. Bake, uncovered, in middle of oven until cheese is melted and bubbling, about 25 minutes.