6 tuna steaks (6 ounces each), cut 1 inch thick

1/4 cup fresh lemon juice

¼ cup clam juice

1/4 cup dry sherry or dry vermouth

1 tablespoon minced fresh ginger

1/4 teaspoon sugar

1/4 cup plus 3 teaspoons olive oil

3/4 teaspoon salt

¼ teaspoon freshly ground pepper

1 medium onion, finely chopped

2 small garlic cloves. minced

1 cup tomato puree

2 medium ripe tomatoes-peeled, seeded and coarsely chopped

3 tablespoons chopped green olives plus

6 olives, sliced into thin strips, for garnish

2 tablespoons Cognac or other brandy, or bourbon

1 tablespoon dried basil

1 bay leaf

1.Place the tuna steaks in a glass dish in a single layer. In a bowl, combine the lemon juice, clam juice, sherry, ginger and sugar. Add 3 tablespoons of the olive oil, ¼ teaspoon of the salt and ¼ teaspoon of the pepper. Mix to blend and pour this marinade over the tuna steaks. Cover and let marinate for at least 2 hours in the refrigerator, turning the steaks once or twice.

2. In a large nonreactive skillet, heat 1 tablespoon of the olive oil. Add the onion and garlic, cover and cook over low heat, stirring occasionally, until softened, 10 to 15 minutes. Add the tomato puree, fresh tomatoes, chopped green olives, Cognac, basil, bay leaf and the remaining ½ teaspoon salt and ¼ teaspoon pepper. Cook over very low heat, stirring occasionally, until the sauce thickens, about 20 minutes. Set aside.

3. Preheat the oven to 400. Remove the tuna steaks from the marinade and pat dry with paper towels. Pour the marinade into a small nonreactive saucepan and cook over high heat until thickened slightly, about 5 minutes.

4. In a large heavy skillet, preferably cast iron, heat 1 teaspoon of the olive oil over moderately high heat until almost smoking. Add 3 of the tuna steaks and cook, turning once, until well browned, about 1 minute per side. Using a spatula, transfer the seared tuna to a shallow baking pan. Repeat with the remaining 1 teaspoon olive oil and 3 tuna steaks. Bmsh the reduced marinade over the tuna steaks and bake until just cooked, 5 to 6 minutes for medium-rare.

5. Reheat the tomato sauce over moderate heat. Spoon the sauce onto 6 serving plates. Thickly slice the tuna steaks on the bias, if you like, or arrange them whole on top of the sauce. Garnish with the sliced olives.