Heat oil in a large pot over medium heat
Whisk in flour to make a roux
Stir constantly until the roux turns dark brown
Add chopped onion, celery, and bell pepper
Cook until vegetables soften
Add garlic and cook briefly
Add broth and stir well
Add okra or filé if desired
Add chicken, sausage, shrimp, or crab
Season with salt, pepper, thyme, bay leaves, and cayenne
Simmer on low heat until flavors blend
Cook until meat is done and seafood is tender
Serve over cooked rice
Garnish with green onions or parsley if desired