1. In a 10- to 12-inch frying pan, melt 4 tablespoons of the butter over moderate heat. Add the fresh or frozen okra and, stirring constantly, cook until the okra stops "roping," that is, until the white threads the vegetable produces disappear.
2. Over moderate heat, melt the remaining 4 tablespoons of butter in a heavy 2- or 3-quart soup pot or casserole. When the foam subsides, add the onion, green pepper and garlic, and cook without browning for about 5 minutes.
3. Stir in the 2 tablespoons of flour, and when it has been absorbed by the vegetables, cook 2 to 3 minutes longer, stirring constantly.
4. Pour in the chicken stock and stir with a whisk to dissolve the flour. Then add the okra, the tomatoes, the herb bouquet, thyme, salt and a few grindings of black pepper.
5. Bring to a boil, turn the heat to its lowest point. and simmer, partially covered, for ½ hour. Then drop in the shrimp, simmer for 5 minutes and add the crab meat and oysters.
6. Simmer for 2 or 3 minutes, or only until the oysters curl around the edges and the crab meat is heated through. Season with the lemon juice, Worcestershire sauce and the ¼ teaspoon Tabasco, or more to taste.
7. To serve, it is customary to ladle the gumbo over small , mounds of hot rice in deep soup plates. However, the rice may be omitted if you prefer.
