Have lots of leftover turkey? Skip the boring next-day sandwiches and make chef David Slater's hearty turkey gumbo instead.
Combine the oil and flour in a large cast-iron pot or enameled cast-iron Dutch oven, over medium heat. Stirring slowly and constantly for 20 to 25 minutes, make a dark brown roux, the color of chocolate.
Season the onions, bell peppers, and celery lightly with salt and cayenne. Add this to the roux and stir until the vegetables are soft, about 5 minutes. Add the sausage, the dried thyme and oregano, and cook, stirring often, for 5 minutes. Add the broth and bring to a boil. Reduce the heat to medium-low and simmer, uncovered, for 45 minutes. Add the reserved turkey meat and cook for 15 to 20 minutes, until flavors have mingled and the turkey meat has softened, but not completely shredded apart. Add the parsley and green onions.
Serve in soup bowls with rice. (File powder can be added at the table according to personal taste.)