In a large bowl, combine the yellow onions, bell peppers, celery, and ½ cup of the green onions (set aside the remaining ½ cup of green onions). In another bowl, stir together Old Bay Seasoning, bay leaves, salt, black and white pepper, cayenne, thyme, oregano, and cloves to make the spice mix.
Heat a heavy saucepan on medium-high and add the vegetable oil. Stir in the flour to make a smooth roux. Turn the heat to medium and cook the roux, stirring frequently, until it slowly turns a deep nutty-brown color, about 30 minutes. While you are cooking the roux, pour the shrimp stock into a large soup pot and begin heating it to a simmer.
Add the onion, bell pepper, and celery mixture to the roux and stir to combine, cooking for about 2 minutes. Stir in the garlic and the spice mixture—the ingredients will come together in a sticky mass—and cook for another minute while stirring.
Turn the heat up to high under the soup pot with the shrimp stock and start gradually adding the roux mixture, whisking between additions to incorporate the roux. Once all the roux has been added, bring gumbo to a brisk simmer and cook for 15 minutes, stirring occasionally. If any foam floats to the surface of the pot, skim off with a spoon or ladle.
Add the reserved ½ cup of green onions, the parsley, and the shrimp to the simmering gumbo and cook for 3 minutes. From this point on, avoid heating the mixture any higher than a simmer to keep from overcooking the seafood. Next, stir in the oysters with their liquor and continue cooking at a low simmer for about 1 minute. To finish the gumbo, gently stir in the crabmeat.
Serve immediately, mounding about ¼ cup of cooked rice in the middle of each bowl and ladling the gumbo over the top, making sure that everyone gets some shrimp and oysters. Serve with crusty French bread, passing a bottle of hot sauce and the filé at the table.
Notes
Adapted from Big Ranch, Big City Cookbook, by Louis Lambert, with June Naylor. Published by Ten Speed Press.