Gwyneth Paltrow's Grilled Tuna Rolls

Ingredients

• For the grilled tuna rolls:
• 2 tablespoons sweet white miso paste
• 1 tablespoon vegetable, sunflower, or rice bran oil
• 1 tablespoon light agave nectar
• 1 teaspoon water
• 1 tablespoon rice wine vinegar
• Pinch fine salt
• 2 1/2-inch-thick tuna steaks or 1 large tuna steak, cut in half horizontally
• 2 tablespoons sesame seeds, divided
• 4 hot dog buns
• 1 head butter lettuce, leaves separated
• 1/4 cup Shallot & Cilantro Vinaigrette, for serving, recipe follows
• 2 tablespoons fresh cilantro leaves, for serving
• For the shallot & cilantro vinaigrette:
• 2 1/2 tablespoons rice wine vinegar
• 1 tablespoon soy sauce
• 1/4 cup vegetable or sunflower oil
• A few dashes of hot pepper sesame oil or your favorite hot sauce
• 2 shallots, peeled and very thinly sliced
• 1 tablespoon roughly chopped fresh cilantro

Directions

1. Heat a grill or grill pan over high heat. In a bowl, whisk the miso, oil, agave, water, and rice wine vinegar until smooth, then add salt to taste. Coat the tuna steaks on every side with the miso mixture and set them on the grill. Scatter 1 tablespoon of the sesame seeds evenly over the fish. Cook the first side for 3 minutes, turn the tuna over, and cover the seared side with the remaining sesame seeds. Grill for an additional 3 minutes, then transfer the fish to a plate. This timing gives you tuna that is just cooked through; if you want it medium or rare, take it off the grill sooner.
2. For serving, grill or toast the buns. Arrange a few lettuce leaves on the bottom half of each bun. Slice the tuna across the grain into 1/2-inch pieces and divide it evenly over the lettuce. Spoon a tablespoon of the vinaigrette over each sandwich, making sure each one gets plenty of the sliced shallots, then add the cilantro leaves. Set the top halves of the buns in place and serve with lots of napkins.
3. To make the Shallot & Cilantro Vinaigrette, whisk together the vinegar, agave, and soy sauce. Keep whisking as you slowly pour in the vegetable oil. Add hot pepper sesame oil to taste, then stir in the shallots and cilantro. If it has been made ahead, stir it well again before serving.