Ingredients 1 1/2 pounds fresh tuna steak2 cloves garlic , chopped2 inches fresh ginger root , minced or grated3 tablespoons tamari dark soy sauce2 scallions , chopped1/2 small red bell pepper , finely chopped2 teaspoons sesame oil (eyeball the amount)2 teaspoons grill seasoning blend (recommended: Montreal Steak Seasoning by McCormick) or 1 teaspoon black pepper and 1/2 teaspoon coarse salt (eyeball it)1 tablespoon light-in-color oil , such as canola, safflower or peanut oil1/2 pound shiitake mushrooms , coarsely choppedCoarse salt4 sesame kaiser rolls , split1 jar (8 ounces) mango chutney4 leaves red leaf lettuce1 jar (8 ounces) wasabi mustard (recommended: Stonewall Kitchen brand)Exotic root vegetable chips (recommended: Terra brand), to pass at table, optionalPickled ginger , optional plate garnish
Preheat a nonstick griddle or a grill pan to high heat.
Cube tuna into bite size pieces and place in a food processor. Pulse the processor to coarse-grind the tuna; it should take on the consistency of ground beef or turkey. Transfer tuna to a bowl. Combine ground tuna with garlic, ginger, dark soy sauce, scallions, red bell pepper, sesame oil, seasoning blend and black pepper. Form 4 large patties, 1 1/2 inches thick. Drizzle patties on both sides with light-in-color oil, such as canola, safflower or peanut oil.
Cook tuna burgers 3 minutes on each side for rare, up to 6 minutes each side for well done. Preheat broiler.
In a medium nonstick skillet over high heat, sauté fresh shiitakes for 2 or 3 minutes in 1 tablespoon light oil—1 turn of the pan in a slow stream. Season mushrooms with salt and pepper.
Open up the rolls and lightly toast them under the broiler. Spread mango chutney on the bottom of each bun. Top with tuna burger, shiitakes, red leaf lettuce. Spread wasabi mustard or sweet hot mustard on bun tops and set them in place. Serve with exotic chips and pickled ginger, if desired.