How to Make a Vegan Tuna Sushi Roll Using Marinated Watermelon

|Updated Jun 20, 2022

This vegan Watermelon Tuna is a total game-changer. It’s a healthy and delicious fish alternative, that has an amazing taste and texture that resemble real tuna. Make this recipe on National Sushi Day this Saturday, June 18th!

Making Watermelon Tuna is really simple. All you need to do is marinate your watermelon for a few hours. The watermelon will soak up all the goodness and after frying, the texture will change as well.

The marinade for the Watermelon Tuna is made of soy sauce, toasted sesame oil, lime juice, maple syrup, fresh garlic, ginger, and chili. You can also add some crumbled seaweed to this mixture to make the taste fishier.

Once you combined your marinade ingredients, you prepare the watermelon. Depending on what you plan to use your vegan tuna for, you can cube, slice, or dice the melon to whatever size you need (or fits in your container).

This watermelon tuna is naturally vegan and gluten-free (without the breading), and can be also made oil-free. However, I wouldn't suggest doing it. The toasted sesame oil gives a very intense flavor to the Watermelon Tuna. So if you leave it out you're gonna lose a lot of taste.

You can prepare this Watermelon Tuna in different ways:

Keep it raw: After marinating you can keep this ’tuna’ raw and use it directly. It’s best when the watermelon is cut into smaller pieces, and used for salad, buddha bowls, or as a bread topping.
Fried or grilled: After marinating sear the slices in a pan or grill pan. This will completely change the texture of the watermelon tuna. It’s best for sushi, appetizers, and served as a steak with salad, rice, or wok veggies.
Breaded, then fried: This version is a really tasty and indulgent one. The soft and juicy tuna pieces are covered with crispy bread coating, then fried to perfection. This version is great to put in sushi, to top salads with, or to serve as a main dish with a salad on the side.

What watermelon to use?

Seedless watermelon is the best to use here. You can use both red and yellow versions.
Option for non-seedless: If you can't find seedless watermelon anywhere, just try to get watermelon slices with as less seeds as possible. You can remove some of the seeds, but be careful not to make too large holes - otherwise breading will be difficult.
Ripe level: Your watermelon should be ripe, but not overly ripe or mushy.

Prep time: 10 mins
Marinating time: 2+ hours
Cook time: 5 mins

Watermelon Tuna

Ingredients

10 oz/300 g seedless watermelon (cut into 4 x 2 inch/10 x 5 cm blocks)

For the marinade

3 tbsp dark soy sauce
1 lime, juiced
1 tbsp maple syrup
1 tbsp toasted sesame oil
2-3 cloves of garlic, minced
1 fresh chili, sliced
A thumb-sized piece of ginger, grated
1/2 tsp chili flakes
1 nori sheet, crumbled (optional)
salt, pepper

For the breading (optional)

4 tbsp unsweetened plant milk
1 oz / 30 g flour
2 oz / 55 g breadcrumbs
4 tbsp sesame seeds
vegetable oil for frying

Instructions

In an air-tight container mix together soy sauce, lime juice, maple syrup, sesame oil, garlic, chili, ginger, chili flakes, and nori. Taste, and season with salt and pepper if needed.
Place watermelon into the marinade, and place in the fridge for at least 2-12 hours.

For the sashimi version

Heat up a pan over medium-high heat. Place watermelon blocks into the hot pan, and sear for 2-3 minutes on each side, or until slightly charred.
Alternatively bake watermelon blocks at 400°F/200°C for about an hour in the oven.
Cut watermelon into smaller cubes or thin slices, depending on how you'd like to use it.

For the breaded version

For the breading mix together plant milk and 2 tablespoons of flour in a bowl. In a separate bowl mix together breadcrumbs and sesame seeds. In a third bowl place rest of the flour.
Drain watermelon blocks, and dip them into the flour, making sure they are thinly, but fully covered.
Then using a clean fork or spoon place them into the milk flour mix. Roll around to cover everywhere, then shake off any excess.
Using another clean fork or spoon, transfer watermelon blocks to the breadcrumb mixture, and generously coat them.
Heat up vegetable oil in a deep fryer or a pot. Place watermelon blocks into the hot oil, and fry for 2-5 minutes, or until golden. Depending on the size of your fryer, you might need to work in batches.
Transfer watermelon blocks to a paper towel-lined plate, and let cool a bit before slicing.

Nutritionals: 2 Servings