In a large sauce pan, over medium heat, melt the butter. Add the onions, peppers, and celery to the pan. Season the vegetables with salt and cayenne. Saute the vegetables until they are wilted, about 6 to 8 minutes. Stir in the bay leaves, tomatoes, and garlic. Bring the mixture to a boil and reduce to a simmer; continue to cook for 15 minutes.
In a small bowl whisk the flour and water toghether and add the mixture to the tomatoes. Cook for 4 to 5 minutes. Add the shrimp stock, Worcestershire and hot sauce and continue to cook for 10 minutes longer.
Season the shrimp with Essence and add them to the pot. Cook the shrimp ntil they are pink and cooked through,about 6 to 7 minutes. Stir in the green onions and parsley.
Serve with white rice.
Yield: 6 servings