4 dried ancho chiles, stemmed, seeded, and torn into ½-inch pieces (1 cup)
4 dried New Mexican chiles, stemmed, seeded, and torn into ½-inch pieces (1 cup)
3 tablespoons vegetable oil
1 large onion, chopped
6 garlic cloves, minced
¾ teaspoon ground cumin
¾ teaspoon dried oregano
Salt and pepper
3 cups chicken broth
1 ¼ pounds boneless, skinless chicken thighs, trimmed
1 ½ tablespoons cider vinegar
sugar