PreparationFor tapenade: Stir 1/3 cup olive oil, next 4 ingredients, and anchovy, if using, in a small bowl. Add more olive oil for a thinner tapenade, if desired. (For a smoother sauce, purée tapenade in a food processor or blender.) Set aside. For steak: Place steak in a large baking dish and season generously with salt. Stir orange zest and juice and remaining 6 ingredients in a small bowl to combine. Spread mixture evenly over both sides of steak and let marinate at room temperature for 1 hour. Build a medium-hot fire in a charcoal grill, or heat a gas grill to high. Grill steak, turning once, until nicely charred, about 5 minutes on each side for medium-rare. Transfer to a carving board and let rest for 5-10 minutes. For tomatoes: Arrange tomatoes on a serving platter. Scatter shallot and parsley over; drizzle with oil and season with salt and pepper. In a medium bowl, toss watercress with 1 tablespoon each oil and lemon juice. Season watercress to taste with salt. Mound watercress on platter. Slice steak against the grain; transfer to platter with tomatoes and watercress. Spoon tapenade on steak and serve alongside.
PreparationFor tapenade: Stir 1/3 cup olive oil, next 4 ingredients, and anchovy, if using, in a small bowl. Add more olive oil for a thinner tapenade, if desired. (For a smoother sauce, purée tapenade in a food processor or blender.) Set aside. For steak: Place steak in a large baking dish and season generously with salt. Stir orange zest and juice and remaining 6 ingredients in a small bowl to combine. Spread mixture evenly over both sides of steak and let marinate at room temperature for 1 hour. Build a medium-hot fire in a charcoal grill, or heat a gas grill to high. Grill steak, turning once, until nicely charred, about 5 minutes on each side for medium-rare. Transfer to a carving board and let rest for 5-10 minutes. For tomatoes: Arrange tomatoes on a serving platter. Scatter shallot and parsley over; drizzle with oil and season with salt and pepper. In a medium bowl, toss watercress with 1 tablespoon each oil and lemon juice. Season watercress to taste with salt. Mound watercress on platter. Slice steak against the grain; transfer to platter with tomatoes and watercress. Spoon tapenade on steak and serve alongside.