In a large enameled cast-iron Dutch oven over medium-low heat, add the vegetable oil.
Gradually begin sprinkling in the flour while stirring constantly.
Continue stirring the roux over medium-low heat and be patient. Depending on your stove and how dark you like your roux, this can take upwards of an hour or possibly even a little longer. As it cooks, you’ll see the roux gradually move through different shades of brown. You're looking for something around a medium brown, similar to milk chocolate, with a rich, nutty, almost buttery aroma.
Once the roux reaches that beautiful milk-chocolate color, immediately add the onion, bell pepper, and celery.
Keep stirring as the vegetables begin to soften.
Add the fresh minced garlic and cook until aromatic.
Stir in the chicken bouillon powder, Cajun seasoning, dried thyme, and filé powder.
Add the Worcestershire sauce and hot sauce.
Slowly pour in the chicken stock while continuing to stir. Make sure you scrape along the bottom of the Dutch oven and work everything together until the roux is completely incorporated into the stock and you have a smooth base for the gumbo.
Add the chopped parsley and sliced green onions, followed by the browned Andouille sausage giving it all another good stir.
Cover the Dutch oven and bring the gumbo to a boil.
Carefully add the chicken thighs and bay leaves ensuring the chicken is fully submerged.
Cover the pot, and let everything cook for about an hour.
After an hour, remove the chicken thighs and bay leaves.
Discard the bay leaves, then shred the chicken into bite-sized pieces.
Return the shredded chicken to the pot along with the sliced okra.
Reduce the heat and let the Chicken and Sausage Gumbo simmer for another 45 minutes.
Serve it hot with cooked white rice, a side of homemade Southern cornbread, and, of course, some Louisiana or Crystal Hot Sauce.