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Murielle Banackissa
Watermelon Vegan Tuna with Spicy Mayo Sauce

Watermelon Vegan Tuna with Spicy Mayo Sauce

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4 hours 15 mins Prep: 10 mins Cook: 2 hours 5 mins Marinating time: 2 hours
Serves 2

This recipe for juicy, salty, melt in your mouth vegan tuna made out of watermelons will be your new favorite poké bowl add on!


  • 700 g of watermelon , seeds and rind removed and diced into 2cm x 2cm cubes
  • 1 tsp ground seaweed or seaweed flakes
  • 4 tbsp tamari or soy sauce
  • 4 tbsp white rice vinegar
  • 2 tsp sesame oil

Spicy Mayo

  • 2 tbsp vegan mayo
  • 2 tsp sambal oelek or sriracha , or more to taste

For Serving

  • Green onions , sliced
  • Black and white sesame seeds


  1. Step 1

    In a large airtight container, add watermelon, seaweed, tamari, white rice vinegar and sesame oil. Put on the lid and shake gently to distribute the seasonings.

  2. Step 2

    Place in the fridge for at least 2 hours and up to 24 hours to marinate.

  3. Step 3

    After marinating, preheat oven to 250ºF and line a baking sheet with parchment paper.

  4. Step 4

    Place all the cubes on the parchment paper. Reserve the sauce to use in another recipe such as an Asian sauté or a pad Thai.

  5. Step 5

    Bake for 2 hours, flipping the cubes halfway through.

  6. Step 6

    After 2 hours, increase oven temperature to 350ºF and bake for 5 more minutes, until slightly charred.

  7. Step 7

    Transfer into an airtight container, close and place in the fridge until cold.

  8. Step 8

    Once cold, and right before serving, mix vegan mayo and sriracha together and add into the container with your watermelon. Toss to coat.

  9. Step 9

    Serve immediately in vegan sushi, in my Spicy Tuna Poke Bowl or even as a garnish on an avocado toast.

Common Questions & Swaps

  • Can I use a watermelon with seeds? Yes, of course, you will have to remove the seeds though before baking it.
  • Can I swap tamari with soy sauce? Yes absolutely!

  • Can I double the recipe? Yes you can for the amount of watermelon, but I would not double the amount of tamari, seaweed, vinegar or sesame oil. I would only multiply the measurements for those by 1 1/2. So for example, if you want to double the amount of watermelon from 700 grams to 1,400 grams, increase the amount of tamari to 6 tablespoons instead of 8.

  • Do I have to serve this with a spicy vegan mayo? Absolutely not. You can keep it as is; I just like the spicy mayo because it adds a level of creaminess that I personally enjoy.

Vegan Watermelon Spicy Salmon-14
Vegan watermelon tuna in a small bowl. Garnished with sesame seeds and green onions
Vegan watermelon tuna in a small bowl with chopsticks next to it. Garnished with sesame seeds and green onions