Make a dark roux
Add the onions, bell peppers, and celery and cook until softened
Add the garlic and cook for 1 minute
Stir in the chicken, sausage, and shrimp
Pour in the chicken broth and add the tomatoes, okra, Cajun seasoning, bay leaves, and thyme
Simmer for 30-45 minutes
Stir in the file powder just before serving
Serve over rice
