Gumbo is a staple of new orleans cuisine, and with this recipe, even vegetarians and vegans can enjoy this classic dish. Like traditional gumbo, this vegetarian version includes the requisite celery, onions, bell peppers, tomatoes, and okra, making this a creole-style or louisiana vegetarian gumbo rather than a cajun one (which omits the tomatoes). Gumbo isn't traditionally made vegetarian, so there's not really a wrong or a right way to make it. The recipe does call for fil powder (made from the sassafras tree) for seasoning, and though it's difficult to find in mainstream grocery stores, there's not really a good substitute. You can omit it without too much trouble and just add a touch more thyme and salt, and maybe also a touch of something savory and neutral to add flavor (like garlic powder, celery seed, or a dash of a creole seasoning blend if you have one). If you need it to be gluten-free, just be sure to use a gluten-free vegetable broth or substitute water instead.