1/4 cup vegetable oil (I use canola in this recipe)
1/3 cup all-purpose flour
1 medium onion, chopped
1 medium green bell pepper, seeded and diced
1 cup celery, chopped
1-2 garlic cloves, minced
1 28-oz can diced tomatoes in juice
3 cups fresh or frozen okra, sliced
1 cup frozen corn (optional)
4 cups vegetable broth
1 tsp dried thyme
1 tsp paprika
1 tsp dried oregano
1 tsp hot sauce (Tabasco) or more to taste
1 1/2 tsp filé powder (gumbo filé- Sassafrass leaves )
salt and black pepper to taste
To prepare the roux, heat the oil over medium heat in a large pot. Add flour while stirring constantly until oil and flour are well mixed. Cook the roux for a few minutes, until it turns golden brown color, stirring constantly. Add onion, celery and bell pepper, and cook 3 minutes. Stir in all ingredients besides the file powder and hot sauce. Bring to boil. Reduce heat to low and simmer for 50 minutes, stirring occasionally. Add hot sauce and season with salt and black pepper. Remove the pot from the stove. Sprinkle with filé powder , cover and let sit for 15 minutes. Stir and serve over rice.
Important note about filé powder. You do not have to use it in this recipe, but it gives the gumbo more authentic Louisiana flavor and it thickens it up nicely.
Remember that filé powder should never be added to a pot of gumbo while it is still cooking, but rather at the end when the gumbo is removed from the stove. Otherwise you will get some strange and stringy texture in your gumbo.
If you don't have fresh celery, onion and green bell pepper, you can buy them frozen. Most stores sell this frozen "Trinity" (celery, onion and bell peppers) which is the base for most Louisiana cooking.