Saute onions, bell pepper, garlic and celery in roux. Add in crab fat if desired. (Clean crabs by removing back shell, remove spongy gill sections, eggs and small legs. Keep claws. Break body sections in half). Add to roux, onion, bell pepper mixture, cleaned crabs and claws. Add cream of mushroom soup and 2 cups water. Season to taste. Bring to boil and simmer covered 1-1/2 to 2 hours.