King Oyster Mushroom Fish Nigiri Sushi is a vegetarian twist on traditional fish nigiri sushi. Instead of using raw fish, this recipe uses king oyster mushrooms as a substitute. The mushrooms are marinated in a mixture of soy sauce, mirin, and sesame oil, then sliced and placed on top of sushi rice. The result is a delicious and visually appealing sushi that is both healthy and flavorful. This dish is perfect for sushi lovers who are looking for a vegetarian option.