Cut the fish into 2-inch pieces. Season with 1 tablespoon of the Essence and set aside.
In a large, heavy stockpot, heat the oil over medium-high heat. Add the flour and stir constantly with a heavy wooden spoon until it becomes a dark roux the color of chocolate, about 15 to 20 minutes.
Add the celery, onions and bell peppers, and cook, stirring, until the vegetables are wilted, 6 minutes. Add the bay leaves and garlic, and cook for 2 minutes. Add the tomatoes, wine, stock, salt and cayenne, and stir well. Bring to a boil and reduce heat to medium-low. Simmer uncovered, stirring occasionally, until thickened, about 30 minutes. Add the fish and cook until it flakes with a fork, about 10 to 15 minutes. Stir in the green onions and parsley during the last 5 minutes of cooking time.
Remove the bay leaves and serve hot in soup bowls ladled over rice.
Yield: Makes 4 servings