1 tablespoon unsalted butter
1/2 pound andouille sausage, cut into 1/3-inch-thick slices
1 1/2 cups frozen trinity mix, thawed and drained
2 tablespoons chopped fresh thyme
1 tablespoon minced garlic
1 tablespoon Cajun seasoning
1 bay leaf
4 cups low-sodium chicken broth, divided
1 cup dry roux, sifted
3 cups shredded rotisserie chicken
Kosher salt and ground black pepper, to taste
1 1/2 teaspoons filé powder
Frozen long-grain rice, reheated (recipe precedes)
chopped fresh parsley
In a large Dutch oven, heat butter over medium-high heat. Add andouille; cook, stirring frequently, until browned, 4 to 5 minutes. (Reduce heat as necessary to prevent overbrowning.) Remove andouille using a slotted spoon, and transfer to a bowl.
Add trinity to Dutch oven; cook, stirring frequently, until vegetables are softened, about 4 minutes. (Reduce heat as necessary to prevent overbrowning.) Add thyme, garlic, Cajun seasoning, and bay leaf; sauté, stirring frequently, until fragrant, 30 seconds to 1 minute. Stir in 2 cups broth, scraping browned bits from bottom of pot with a wooden spoon.
In a large bowl, whisk together dry roux and remaining 2 cups broth. Add roux mixture to pot with andouille; bring to a boil. Reduce heat to medium-low; simmer for 20 minutes, adding chicken during last 5 minutes of cooking time. Discard bay leaf. Season to taste with salt and pepper. Stir in filé powder. Serve immediately with rice. Garnish with parsley, if desired.