Bring the stock to a simmer in a large pot. Gradually spoon in the roux until your desired thickness is achieved. After each spoonful, let the mixture come to a simmer so you can see the full effect of the thickening. Once desired thickness is achieved, add all the seasonings and bring back to a simmer. Be careful not to boil vigorously, gumbo should be cooked at a gentle simmer the whole way through.

Add the onions, bell peppers, celery, and tomatoes. Adjust seasonings, to taste. Once the gumbo comes back to a soft boil, add crab legs, littlenecks, and scallops and cook for 15 minutes, or until the mixture again reaches a soft simmer. Finally, add your okra, shrimp, and green onions and cook until all seafood is cooked through and flavors are combined, about 15 to 20 minutes. Discard any unopened clams.

Making gumbo is a time consuming process. It would be best to make your gumbo a day ahead; this will allow all the flavors to marry well. Serve your gumbo over white rice and make sure you don't forget the file powder. Enjoy!