In a large Dutch oven, heat the avocado oil over medium heat.
Slowly whisk in the cassava flour, stirring constantly for 8 to 10 minutes until the roux reaches a deep chocolate brown color.
Add the diced onion, green bell pepper, and celery to the roux, sautéing until the vegetables are softened and fragrant.
Stir in the minced garlic, sliced andouille sausage, and diced chicken breast, cooking for 3 minutes to lightly brown the proteins.
Gradually pour in the chicken bone broth while stirring to incorporate the roux, then add the Creole seasoning, sea salt, and black pepper.
Bring the mixture to a boil, then reduce heat to low and stir in the sliced okra.
Cover and simmer for 20 minutes until the chicken is cooked through and the gumbo has thickened.
Serve the gumbo in a bowl topped with a scoop of warm brown rice and a sprinkle of fresh parsley.