
Trim fat from meat. Cut meat into ¾-inch pieces. In a large skillet heat oil over medium-high heat. Add meat, half at a time, and cook until brown. Drain off fat.
Transfer meat to a 3 ½- or 4-quart slow cooker. Stir in beans, tomatillos, onion, chile peppers, garlic, cumin, and salt. Pour broth over mixture in cooker.
Cover and cook on low-heat setting for 6 to 7 hours or on high-heat setting for 3 ½ to 4 hours.
Stir in spinach and lime juice. If desired, top each serving with sour cream and/or cilantro.