Gumbo is one of New Orleans' most emblematic dishes. In true Creole fashion, Tujague's version incorporates meat and seafood and is thickened with filé—ground sassafras—instead of okra. Every gumbo is different, but one rule remains firm. Filé powder is never combined with okra in a gumbo.
For the gumbo:
Add the shrimp stock to a large stockpot or Dutch oven set over medium heat. If the stock comes to a boil, reduce the heat to the lowest possible temperature while keeping it hot.
Heat the oil until shimmering in a heavy skillet set over medium-high heat. Add the flour and cook, stirring constantly with a wooden spoon, until a dark roux is achieved, about 10-15 minutes, depending on how high your heat is. Add the onion and cook, stirring constantly until the onions are softened and translucent, about 3 minutes. Add the celery and green pepper and cook until softened, about 5 minutes. Add the shrimp stock to the roux and vegetables, then bring the mixture to a boil. Add the sausage, gumbo crabs, and salt and pepper or Creole seasoning to taste. When the mixture comes to a boil, reduce the heat to a low simmer and cook until the mixture is thickened and fragrant, about 1 hour.
Add the shrimp, crabmeat, oysters, parsley, and green onions. Cook until the shrimp are pink and the edges of the oysters ruffle, about 5 minutes. Stir in the filé powder.
Serve the gumbo over rice.
For the shrimp stock:
Place all of the ingredients in a large pot. Bring the mixture to a boil, skimming any foam as necessary. Continue to boil until reduced by one-fourth, 15-20 minutes. Strain the stock and discard the solids. Chill the stock.