How to Make It
In a large pot, combine the oil and flour and cook over moderately high heat, stirring constantly, until golden, about 5 minutes. Add the onion, celery, bell peppers and garlic and cook over moderate heat, stirring frequently, until the vegetables are tender, about 10 minutes. Stir in the tomato paste and cook for 1 minute. Add the chicken stock, Worcestershire sauce, oregano, thyme and bay leaf and bring to a simmer. Add the andouille and okra and simmer over low heat until the okra is broken down and the gumbo is thickened, about 2 hours. Season with salt and pepper. Discard the bay leaf.
Preheat a grill pan or light a grill. Brush the chicken with the olive oil and season with salt and pepper. Grill over moderate heat, turning once, until lightly charred and cooked through, about 10 minutes. Let the chicken rest for 5 minutes, then thinly slice it crosswise.
Spoon the gumbo into shallow bowls. Top with the chicken and scallions and serve with rice and hot sauce.