Halve and seed chilies. Place on a baking sheet and broil for 5 minutes. Then place them in a paper bag and seal it.
Peel the tomatillos. Put them on the baking sheet and broil for about 15 minutes, turning once.
While the tomatillos are cooking heat the oil in a frying pan. Add onion, carrots, celery and bell pepper and saute for 2 minutes. Add flour and stir it for 2 more minutes. Add garlic and saute for another 30 seconds.
Take the chilies out of the bag and peel them. Combine them with the tomatillos, cilantro, cumin and 1 c. of chicken broth in a blender and blend.
Mix together the blended tomatillo mixture, sauted vegetables and all the remaining ingredients in a slow cooker and cook on low for 4 or 5 hours.