Directions

• Peel the shrimp and set the shells and heads aside in a bowl in the refrigerator. Bring a large pot of salted water to a boil.  Add the crabs and a generous amount of salt, cover the pot, and boil for 5 – 7 minutes.  Drain immediately and set the crabs aside to cool.  (If you were going to fully cook the crabs, you would boil them for 10 – 15 minutes, but you want to leave most of the flavor in the crab to cook in the gumbo, so here you’re cooking them enough to take them apart.
• To make the seafood stock, put the chopped onion and celery and smashed garlic cloves in a medium mixing bowl and set aside.  Peel the front flaps and tops off the crabs and place in a large bowl with the shrimp heads and shells.  Use your fingers to scoop out the orange back fat from the middle of the crab and set aside in a small bowl.  Break the crab bodies into four pieces and set aside for the gumbo.
• Heat the oil in a large pot over high heat.  Add the reserved shrimp shells and heads and the crab shells.  Cook, stirring until the shells turn pink, 3 – 4 minutes.  Add the coarsely chopped vegetables, paprika, rosemary, bay leaves, and 9 quarts of water and bring to a boil.  Reduce the heat and simmer for 1 hour; strain.
• For the gumbo vegetables, dice the onions, bell peppers, and celery.  Set aside with the jalapeños to add to the roux.
• To make the roux, heat the 3 cups vegetable oil in a large Dutch oven over medium-high heat.  When the oil is hot but not smoking, whisk in the flour and reduce the heat to medium.  Cook, whisking constantly and slowly until the roux has  t sickened and is the color of a dark copper penny, 45 minutes to an hour.
• You’ll want to reduce the heat gradually as you go.  When the roux first begins to take on color, for instance, reduce the heat to medium.
• Continue in this fashion, gradually lowering the heat as the color of the roux deepens. By the end of the cooking, when the roux is appropriately dar, the heat should be on low.  It’s essential to whisk the roux constantly as it cooks (but not so vigorously that you splatter the roux and burn yourself), because if even a small bit of flour sticks to the pot, it will become spotty, scorch quickly, and burn the entire roux.
• Add the onion, bell pepper, celery, jalapeños, and the reserved crab back fat and stir until they are well coated.  Stir in the garlic, salt, paprika, file powder, chili powder, black pepper, cayenne, white pepper, oregano, red pepper flakes, thyme, and hot sauce and continue to cook, stirring for a few minutes.  Add two-thirds of the strained stock and the oyster liquor, bring the mixture to a boil, then reduce the heat and simmer, stirring frequently and scraping the bottom of the pot to ensure nothing clumps and burns, until the mixture returns to a simmer
• Start skimming the oil from the top of the gumbo almost instantly (by the end of the cooking process, the gumbo will have released almost all of the oil from the roux).  
• Continue to simmer and skim for about 1 hour.  Taste the stock.  If it still has a strong roux flavor, gradually add the remaining 1/3 stock (if it doesn’t, freeze the remaining stock for another use) until the flavor tastes more like the stock than the roux. When the flavor has developed and the stock is clearer (with fewer dots of oil), add the oysters, crab meat, and crawfish tails.  Bring the gumbo back to a simmer and simmer for 15 – 20 minutes.  Skim once more and add the shrimp.  Once the shrimp has turned pink, the gumbo is ready to be served.