Preheat the oven to 300°
Peel the garlic cloves and put them in a small oven proof container. I use a small ramekin. Cover the cloves with olive oil. You may need a bit more oil if the container is too big. Put the ramekin in the oven and roast the garlic for 1 hour until golden brown. When finished, drain the oil (keep it) and puree the garlic in a small food processor.
Toss the chicken with about half the cajun seasoning. Season with salt.
Slice the andouille into thin half-rounds. I slice the sausage in half lengthwise first and then thinly slice the halves.
Put 2 tablespoons of the garlic oil into a large heavy pot like a dutch oven and heat over medium high heat until hot but not smoking. Add the chicken and stir-fry for about 3 minutes. Add the sausage and continue to stir and cook for an additional 3 minutes. The goal is to get a little color on the chicken and sausage.
Add the celery, bell pepper and onion and continue to cook for another 3-5 minutes until the veggies are softened and the onion starts to look translucent.
Add the garlic puree, basil, oregano, black and white pepper, and the remaining Cajun seasoning. Mix them in thoroughly. DO NOT ADD the filé powder at this time!!
Add the chicken stock and bay leaf and turn up the heat to bring it to a boil.
Once boiling, slightly reduce heat and stir in the cooled roux a little at a time. Mix each addition well. This step will thicken the gumbo.
Reduce the heat to a simmer. This is a good time to taste and adjust any seasoning. Some people like to add a little Cheyanne pepper or red pepper flakes to spice it up a bit more. Once it is adjusted, cover and simmer for an hour.
While the gumbo is simmering, cook the rice. Follow the directions on the package or use a rice cooker (preferred).
Stir the filé powder (if using) into the gumbo. Serve the gumbo in a bowl with a scoop of rice.