Place the whole chicken in a large pot, cover with water by 2 inches, add 15 ml of kosher salt, and bring to a boil. Reduce heat, cover, and simmer for 30-40 minutes, or until cooked through. Remove chicken to a plate, let cool slightly, then shred the meat and discard bones and skin. Strain and reserve the chicken broth.

In the same large pot or Dutch oven, sauté the sliced andouille sausage over medium heat until browned, about 5-7 minutes. Remove sausage with a slotted spoon and set aside.

Reduce heat to medium-low. Add olive oil to the pot. Gradually whisk in the flour to create a smooth paste. Cook, stirring constantly, until the roux reaches a deep, reddish-brown color, resembling dark chocolate (this can take 20-30 minutes).

Stir in the chopped onion, celery, and bell pepper. Cook until softened, about 8-10 minutes. Add the minced garlic, smoked paprika, and thyme, cooking for another minute until fragrant.

Gradually whisk in the reserved chicken broth, scraping up any browned bits from the bottom of the pot. Add the bay leaves. Bring the mixture to a simmer, then reduce heat to low, cover, and cook for 30 minutes to allow flavors to meld.

Stir in the shredded chicken, sautéed andouille sausage, Worcestershire sauce, and cayenne pepper. Continue to simmer, uncovered, for at least 1 hour, or up to 2 hours, stirring occasionally. If the stew becomes too thick, add more chicken broth.

Remove the bay leaves. If using, stir in the filé powder just before serving. Garnish generously with sliced green onions.

Serve hot over cooked long-grain white rice.