6 corn tortillas (6 inches), halved and cut into 1/4-inch strips
1 small onion, sliced
4 garlic cloves, peeled
1 can (14-1/2 ounces) whole tomatoes, drained
6 cups vegetable or chicken broth
1/4 cup chopped fresh cilantro
1/2 teaspoon salt
1/8 teaspoon cayenne pepper, optional
1-1/2 cups shredded Monterey Jack cheese
1 large avocado, peeled and diced
1 medium lime, sliced and quartered
In a small bowl, combine the ancho pepper and water; let stand for 20 minutes or until pepper is softened. Drain and discard water; set pepper aside.
In a large saucepan, heat 1 in. of oil to 350°. Add half of the tortilla strips; cook and stir until golden brown. Remove with a slotted spoon to paper towels to drain. Repeat with remaining tortilla strips; set aside.
Drain saucepan, reserving 2 teaspoons of oil. In reserved oil, cook the onion, garlic and ancho pepper over low heat until onion is golden brown, about 7 minutes. Remove from the heat; cool slightly. Transfer to a food processor; add tomatoes. Cover and process until smooth.
Return mixture to the pan. Cook, uncovered, over medium heat until mixture has thickened to the consistency of tomato paste, 10 minutes. Add broth; bring to a boil. Reduce heat; cover and simmer for 30 minutes.
Add the cilantro, salt and, if desired, cayenne. Divide cheese and avocado among six bowls; top with the soup, tortilla strips and quartered lime slices.