Mix A in a bowl and form two 1cm/0.4inch thick patties.
Heat the oil in a pan and cook (1). Cook both sides until brown and slightly charred. Add Garlic Dashi Soy Sauce, coating the patties with the sauce.
Meanwhile, toast the hamburger buns and spread the mustard.
Assemble the burgers by placing in order bottom bun, lettuce, patty, cheese, tomato, red onion and top bun.
