Prepare the ingredients – Chop the onions, bell peppers, celery, garlic, and parsley. Slice the andouille sausage.
Make the roux – In a large pot, heat oil and slowly whisk in flour, stirring continuously over medium heat until deep brown (about 20-30 minutes).
Sauté the aromatics – Add onions, bell peppers, celery, and garlic to the roux. Cook until softened.
Add the sausage and chicken – Stir in sliced sausage and seasoned chicken, cooking until lightly browned.
Pour in the broth – Gradually add warm chicken broth, stirring well to combine.
Simmer and season – Let it cook on low heat for 45-60 minutes, adding Cajun seasoning, salt, and pepper to taste.
Add the final touches – Stir in fresh parsley and green onions. Adjust seasoning as needed.
Serve hot – Ladle over warm rice and enjoy!