To a large Dutch oven, add 2 tablespoons of the oil and heat over medium-high heat. Sprinkle the chicken with salt and pepper, then sear until golden brown, 4 to 5 minutes per side. Remove the chicken from the pan and add the andouille, cooking until golden brown. Remove from the Dutch oven and set aside.
Combine the remaining 1/2 cup oil and the flour in the Dutch oven over medium heat. Cook, stirring constantly, to make a deep, dark brown roux, 20 to 25 minutes. Add the onions, celery and bell peppers, then add some salt and cook, stirring, until transparent, 4 to 5 minutes. Add the chicken base, garlic, gumbo file, Cajun seasoning, bay leaves, salt and pepper. Stir for another 2 to 3 minutes. Add 8 cups water to the pot. Using a large whisk, whisk until the roux mixture and water are well combined. Bring to a boil, then reduce the heat to medium-low. Cook, uncovered and stirring occasionally, for 1 hour. (Add more water as needed.)
Turn the heat down to medium and add the chicken and andouille. Cover the pot and simmer for 2 hours. Remove from the heat. Stir in the parsley and scallions and remove the bay leaves. Top with additional parsley and scallions. Serve with the rice. |