After roux is copper penny colored, add onion, celery and pepper. Stir to combine 2-3 minutes until softened.
Add broth, cayenne, bay leaves and body shell of crab, if using. Simmer for 20 minutes.
Remove body shell of crab. Add crab meat, shrimp, andouille sausage, parsley, salt, Cajun seasoning and file powder. Simmer for another 10 minutes.
Serve with rice, chopped green onions and crusty french bread