Tomatoes, specifically Roma tomatoes, are a fantastic substitution for tuna because of their slightly sweet taste and vibrant red color. Roma tomatoes, or Italian plum tomatoes, aren’t too juicy either. This means they’ll maintain their shape and won’t fall apart while you’re biting into your vegan tuna nigiri — a type of sushi that is served plain, unlike sushi and sashimi. According to Plant Based Matters, there are only a few key ingredients needed for you to achieve the right flavor: smoked sea salt, thinly sliced onion, and grated ginger.
The smoked sea salt provides a charred taste that mimics real nigiri and is an integral part of the tomatoes’ marinade, while the sliced onion and grated ginger are used as toppings that add to the experience and make it more like eating authentic sushi. Otherwise, the marinade is simple: soy sauce, toasted sesame oil, and smoked sea salt. After boiling, peeling, coring, and quartering your tomatoes length-wise, you just marinate them until your sushi rice is done. Then, voila! Place the tomatoes on top of the rice, along with the toppings, and you have a beautiful, simple, homemade vegan nigiri.