TUNA BURGER WITH PINEAPPLE-MUSTARD GLAZE AND GREEN CHILE-PICKLE RELISH

Steps:

• To make the glaze, combine the pineapple juice, vinegar, shallot, and ginger in a small nonreactive saucepan and cook over medium heat until reduced by half, about 10 minutes. Transfer to a blender and blend until smooth.
• Return the mixture to the saucepan, add the brown sugar, and cook over high heat, stirring occasionally, until slightly thickened, about 5 minutes. Remove from the heat and whisk in the soy sauce, mustard, and lime juice and season with salt and pepper. Transfer to a bowl and let cool to room temperature. The glaze can be made 1 day in advance and stored in a container with a tight-fitting lid in the refrigerator. Bring to room temperature before serving.
• Meanwhile, to make the relish, preheat the oven to 375 degrees F.
• Put the chiles on a rimmed baking sheet, rub them with the oil, and season with salt and pepper. Roast in the oven until the skins of the chiles are blackened, about 15 minutes. Remove the chiles from the oven, place in a bowl, cover with plastic wrap, and let the chiles steam for 15 minutes. Peel, stem, and seed the chiles and then finely dice them.
• Combine the chiles, pickles, onion, lime juice, honey, cilantro, and oil in a medium bowl and season with salt and pepper. Let sit at room temperature for 30 minutes before serving so that the flavors meld. The relish can be made 8 hours in advance and stored in a container with a tight-fitting lid in the refrigerator. Let come to room temperature before serving.
• Cut the tuna into large pieces and then coarsely chop in a food processor. Do not overprocess. (Alternatively you can chop it by hand with a sharp knife.)
• Whisk together 2 tablespoons of the oil, the mustard, honey, and chipotle in a large bowl. Add the tuna and green onions and gently fold to combine. Divide the tuna mixture into 4 equal portions (about 6 ounces each). Form each portion loosely into a 3/4-inch-thick burger and make a deep depression in the center with your thumb. Place on a plate, cover with plastic wrap, and let chill in the refrigerator for at least 30 minutes before cooking.
• To cook the burgers, heat the remaining 2 tablespoons oil in a sauté pan or griddle (nonstick or cast iron) until it begins to shimmer. Season both sides of each burger with salt and pepper. Cook the burgers until golden brown on the bottom sides, about 3 minutes. Turn over, brush with some of the glaze, and continue cooking until medium, about 3 minutes longer.
• Place the burgers on the bun bottoms, drizzle with more of the glaze, and top with the relish and pickled red onions, if using. Cover with the burger tops and serve immediately.