Place the broth in a pot and bring to a simmer. Add all the spices (Creole seasoning, black pepper, crushed red pepper, chili powder, thyme, chopped garlic, and bay leaf), and simmer for 10-15 minutes. Reduce heat to low to keep it hot until you are ready to use it.
While the broth is heating up, make the roux. Melt the butter in an 8 qt. stockpot on medium heat. Whisk in the flour a little at a time making sure to keep the mixture smooth. Continue stirring and heating until the mixture is foamy at the edges and then reduce heat to the lowest possible setting. Continue cooking the roux, stirring every couple of minutes until dark mahogany, about 1 hour.
Add the broth mix to the roux in small amounts, stirring constantly to keep it smooth. Bring to a boil and then reduce to a simmer.
Caramelize onions in a large stockpot. Once browned, add the peppers & celery and continue cooking until soft. Add the cooked veggies to the roux / broth mix.
Add uncooked rice to the pot (optional). Bring the gumbo to a boil, lower heat, and simmer. Cook, skimming fat as necessary, an additional 45 minutes.
Taste for salt and pepper. The vegetarian gumbo is ready at this point. You may add the Andouille sausage, chicken, and/or shrimp at this point, or leave them on the side for each person to add in if they wish.
Notes
We serve the “meat” on the side to use as mix-ins 1 package (12 oz.) Andouille sausage, sliced thin (1/4 inch) 1 package veggie links, Tofurkey Kielbasa is my favorite 1.5-2 pounds of chicken bone-in thighs, cooked and shredded 2-2.5 lbs boneless skinless breasts chicken, cooked and shredded 2 pounds of jumbo shrimp