Turkey Tonnato

Make filling and prepare roast:Put oven rack in middle position and preheat oven to 350°F.Stir together tapenade, zest, garlic, and rosemary in a small bowl.Arrange turkey, skin side up, on a work surface with narrower, pointed end nearest you. Determine which long side of the breast is thickest, then, starting from that side and holding knife parallel to work surface, cut breast horizontally almost in half, stopping 1 inch from other side. Open breast like a book. Season breast with 1 teaspoon salt and 1/2 teaspoon pepper.

Heat olive oil (2 tablespoons) in a 12-inch heavy skillet until hot but not smoking, then brown turkey, turning occasionally, 8 minutes total.

Transfer to a 13- by 9-inch roasting pan and add wine to pan. Roast turkey, uncovered, until a thermometer inserted diagonally 2 inches into thickest part registers 160°F, about 1 hour.

Transfer roast to a platter to cool, reserving pan juices. Cool roast completely, uncovered, then chill, tightly wrapped in plastic wrap, 2 hours.Make sauce:Purée tuna (including oil), 1/2 cup olive oil, water, lemon juice, anchovy paste, and 4 tablespoons of reserved pan juices in a blender, stopping and scraping down sides as necessary, until very smooth.

Cut chilled turkey roast into 1/4-inch-thick slices, discarding strings, then top with chilled sauce. Bring turkey and sauce to room temperature, about 1 hour.

Serve with lemon wedges, capers, and parsley.