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Murielle Banackissa

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

With all that is going in the world right now, spending time on social media is a routine I have eliminated from my life at the moment. Instead, I have turned back to spending time in the kitchen creating new recipes.

This, for me, has been kind of a coping mechanism. A way for me to take my mind off what is happening, off the hurt, the pain and the anger. 

When I am in the kitchen, focused on the task at hand, focused on measuring, tasting, writing down measurements and steps, I manage to momentarily disconnect from the emotions I have inside in connection to the murders of innocent black people in the United States and the racism that continues to exist around the world. 

I do not want to make this blogpost about this topic, but I wanted to share some of the things that have helped me navigate the situation that has been unfolding before our eyes in the past couple of days.

For me cooking, recipe creation and photography are part of the solution. And that is why I still find it important to keep going and keep creating and sharing my discoveries in the kitchen.


This recipe for watermelon vegan tuna with spicy mayo sauce was inspired by a post I saw on a vegan Facebook group, where a person shared her attempt in making vegan tuna. She shared her approximate steps and some of the ingredients she used and I decided to create a full recipe out of it.

With a little bit of trial and error, I came up with this recipe. These vegan tuna cubes were a true revelation for me! They are so juicy, so flavorful and so different than anything I have had in my life. They literally melt in your mouth!

These little beauties can be used in poké bowls, in vegan sushi rolls or even as a little garnish on an avocado toast to add an extra textural element and a pop of flavor.

On that note, I am telling you guys, you HAVE to try this recipe. It is so surprisingly good and quite addictive!

If you guys give this watermelon vegan tuna with spicy mayo sauce a try, be sure to share it on social and tag me (@muriellebanackissa).

Stay safe out there! My heart goes out to all of you and I hope that these hard times, will result long lasting change, where we can all been seen and treated as equal to each other. I hope we can come out of this situation stronger and more united.

Much love and light!

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