You'll never believe that this 'tuna' recipe is plant-based – it's such a clever hack for savory summer dishes

This sweet and juicy fruit is no stranger to summer menus – bringing a crisp sweetness to savory dishes and making the easiest and most refreshing snack or dessert. And learning how to store watermelon properly has helped me to keep it fresh to use for all my favorite recipes, from Martha Stewart's watermelon punch to Martha Stewart's watermelon dressing, which features a surprise secret ingredient. But recently I've been reading about how to use this particular ingredient for a rather unexpected dish: watermelon tuna.

While it doesn't contain actual fish, this ingenious hack involves marinating watermelon and baking it in the oven for a delicious and savory alternative to tuna steak or even salmon, though it does require some forward planning. You'll need to marinate the fruit for a few hours, and bake it for around an hour. The result? An umami-packed dish that serves as a brilliant vegan alternative to fish; I love adding it to summer salads or serving with rice bowls, sushi-style.

How to make watermelon tuna

• Preheat your oven to 375°F
• Cut watermelon into small slices
• Prepare a dressing using soy sauce, rice vinegar and sesame oil
• Marinate the watermelon for up to 6 hours
• Bake for 45-60 minutes

How to prep your watermelon

Naturally, every watermelon dish begins by picking the perfect watermelon – here, you'll need it to be seedless. 'Start with a firm, seedless watermelon, preferably not too ripe,' explains Chef Miguel Guerra, co-owner of plant-based Latin American restaurant MITA.'You're going to want a dense texture.'

When it's time to cut the fruit, it's worth thinking about presentation. 'Cut the watermelon into thick sashimi-style slices or melon ball it,' suggests Miguel. 'Then trim the rind and remove any visible seeds.'

While a Japanese steel knife or set of HexClad knives would be the ideal tools for perfectly sliced watermelon, not everyone will have these in their kitchen, so a serrated knife like the Mercer Culinary 10-inch bread knife from Amazon will also do the trick.

Perfecting the marinade

I love making Martha Stewart's watermelon dressing for a speedy summer snack, but I'm far less clued up about savory marinades. According to the experts, however, it all starts with soy sauce.

'You'll want to marinate the watermelon pieces in a soy sauce mixture containing sesame oil, rice vinegar, and a small amount of natural sweetener such as maple syrup or honey,' advises Lena Bakovic, a nutritionist at VNutrition. Miguel also suggests adding rice vinegar or mirin, grated ginger and garlic, and a pinch of kombu or dulse flakes. 'Let the watermelon marinate for 6 hours or overnight in the refrigerator,' he adds.

Baking your watermelon

After the marinating process is complete, all that's left to do is get your watermelon slices into the oven.

'Place your prepared watermelon on a rimmed baking sheet lined with parchment paper to prevent sticking and make cleanup easier,' instructs Lena. 'Then bake at 375°F for approximately 45-60 minutes, or until the watermelon is tender.'

Thicker slices might take longer in the oven, but you're looking for a finished product that's 'golden brown in color yet still retains a bit of bite,' explains Miguel.

How to serve

Just as you'd add tuna to appetizers, salads and side dishes, watermelon tuna is surprisingly versatile. 'It tends to pair well with sushi rice, seaweed salad, and fresh greens,' says Lena, while Miguel suggests serving it alongside 'avocado, pickled onions, crispy seaweed, or as a grain bowl topping. You can even cube it and add it to poke bowls or tacos.'

An added bonus is that the watermelon can be served straight from the refrigerator, or at room temperature – so while marinating it might take a few hours, plating it up should be stress-free.

Watermelon tuna FAQs

Does watermelon tuna really taste like tuna?

Watermelon tuna doesn't taste exactly like tuna, since there's no fish involved in the recipe. However, the umami flavor of the marinade and the oven-roasted finish really helps to create a tender texture and a sushi-like feel.

'The texture and flavor of this recipe is definitely different compared to real tuna,' Lena reflects, 'but the main benefit is that it provides a plant-based alternative to traditional tuna. It's also just a fun and creative way to enjoy watermelon.'

Should you wrap the watermelon in foil before cooking?

Wrapping the watermelon in foil isn't usually necessary, but you can 'loosely cover it with foil for the first half of the bake to steam and soften the interior.' suggests Miguel. 'Remove the foil for the second half so that it can caramelize and become stronger with darker flavor and color.'

Shop the essential kit for making watermelon tuna