In a bowl combine 1/2 cup oil, the onions, garlic, tomatoes, black and green olives, anchovy, lemon juice, parsley, basil, oregano, salt, and pepper, and stir until thoroughly blended. Makes about 1 1/2 cups.
Sprinkle the tuna steaks evenly on both sides with the Creole Seasoning.
Heat the remaining tablespoon of olive oil in a large skillet over high heat. When the oil is hot, add the tuna and sautÈ until brown, for about 2 minutes on each side.
To serve, place a tuna steak on each of 4 plates and spoon a generous 1/3 cup of the sauce over each.
Yield: 4 main-course servings