Fill a 14-16-quart pot with two quarts of water and bring to a boil.
Meanwhile, peel and devein the shrimp, keeping the heads and hulls. Set the shrimp aside in cold water. In the large "gumbo pot" boil heads and hulls for 30 minutes to an hour. This will give you Creole gumbo. Strain shrimp heads and hulls from stock and set aside. Discard heads and hull immediately. Otherwise, the next day your kitchen will smell like Bayou St. John.
Clean the fresh crabs … If the crabs are fresh, you must take time to clean them. Discard the hard back shell and some of the so-called "dead man," or yellow insides. Clean and separate crabs and set aside. (Note: If necessary, you can use meat from king, Dungeness, snow or stone crabs for your gumbo).
Before you fire up the stove again, cut up your celery, parsley, peppers, onions and garlic, especially if you're alone and there is no one to help you stir the pots. It takes time peeling the onions and garlic … Put the celery and parsley in a separate container from the other chopped ingredients and refrigerate until needed to keep them fresh.
Place the gumbo pot with the shrimp stock on the stove. Add cleaned crabs and bay leaves. Stir slowly. You don't want your shrimp stock messing up the floor. Add celery, parsley, and tomato paste to the gumbo brewing on the stove. Bring to a boil. Turn down heat, cover, and let simmer.
Here comes the roux -- a thick and flavorful sauce that has become one of the most important staples of Louisiana cuisine. Pour oil or shortening into a separate heavy skillet (please do not use a thin omelet pan) over a medium-low heat. Slowly stir in flour to make the roux. Keep your eyes on the skillet. If the phone rings, let the answering machine pick it up. Cook roux until it has a dark mahogany color. Do not stop stirring until roux appears nutty or grainy. If black specks appear, the roux is burned. Throw it out and start from scratch. A good roux could take 30 to 45 minutes cooking time.
Now you are ready to add the holy trinity of onions, garlic, and green peppers to the roux mixture. Stir ingredients in slowly because the flour is still sizzling. The moisture will begin to disappear. This is when Jean would add another quart or two of water to the gumbo pot. Add roux to the gumbo pot. Bring to a boil, stirring constantly. Lower heat and cover. The kitchen should smell good right now. Pour yourself another cold something-or-other. You're halfway there. Come back to look and stir in an hour or so.
Season to taste: add salt, pepper, thyme, Worcestershire sauce, Tabasco sauce and any Creole seasoning you like. Don't overdo it right now. Let the roux work its magic absorbing all the wonderful ingredients. Gumbo is usually very spicy, but you can keep it mild. Remember, if you have decided to use andouille sausage it is also hot.
Fry sausages and okra with a little bit of the leftover grease. Sprinkle a little leftover flour if the okra is fresh. Add to gumbo pot. Add chopped peeled tomatoes, stirring until well blended. Add more water if necessary. The roux will keep it thick and tasty. Return to a boil and simmer for 10 minutes. Reduce heat and let simmer, uncovered, for 2 1/2 to 3 hours over low heat.
Skim any excess fat. Add shrimp. Stir in slowly as you increase the heat one last time. It's time to stir in the filé powder. Cook another 20 to 30 minutes until the gumbo is thick. Taste and adjust seasonings one more time. Did I mention the rice? Seafood gumbo is served over Louisiana rice. Of course, you can substitute for your own favorite rice. Just plain old brown or white rice will do. Before serving, taste one more time and adjust seasoning. Turn off heat and remove seafood gumbo from the stove.
To cool down the pot before serving, place it in the sink with a few inches of ice-cold water. If needed, add additional salt and Tabasco sauce. If you can see through the gumbo to the bottom of the pot, work on your roux next time.