In a large stockpot combine oil and flour and cook over medium-high heat about 15 minutes or until it turns very dark brown, almost between brown and black.
You will have to stir almost constantly. This is called the roux.
Add onions, parsley, celery, bell peppers, scallions and garlic and cook about 10 more minutes or until vegetables are tender, stirring regularly.
Add broth, salt, and creole seasoning.
Cover pot and simmer 15 minutes stirring occasionally.
Add your chosen combination of meat at this point and simmer an additional 10 minutes (if using whole pieces of crab like claws, or blue crab halves cook a little longer to ensure they’re cooked all the way.).
Serve over white rice.