1. Heat a large skillet over medium heat. Toast the dried chiles for 2 to 3 minutes, turning once, until fragrant. Cut chiles in half; remove seeds and stems. Combine chiles with hot water to cover. Let stand 20 minutes, until softened. Meanwhile, toast garlic in skillet over medium heat, turning, until skin is blackened on all sides (15 minutes). Remove skins and discard. Drain chiles. Puree chiles, garlic, oregano, 1/2 teaspoon salt, cumin, 1/4 teaspoon pepper, and chicken broth in blender until nearly smooth.
2. Combine 1 1/2 teaspoons salt and 1/2 teaspoon pepper in large bowl. Add cubed beef and toss to coat.
3. Heat 2 teaspoons oil in large Dutch oven. Add one third of the beef and cook 4 to 5 minutes, until browned. Transfer to another bowl. Repeat process two more times, adding 2 teaspoons oil for each batch.
4. Add onions to drippings and cook 5 minutes, until softened. Stir in chile paste, bell pepper, tomatoes, and beef. Bring to a boil. Reduce heat; cover and simmer 1-1/2 to 2 hours, until beef is tender. Serve with sour cream, tortillas, and beans. Makes 6 to 8 servings.