Watermelon “Tuna” Steaks To Blow Your Mind! - Tasty Thrifty Timely

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Top down view of watermelon "tuna" steaks displayed on a plate with grill lines seared into the fruit.

I'll take my watermelon grilled please! Wow! This recipe far exceeded my expectations. I could not believe how "fish-like" the texture of watermelon became once baked! They're left to marinate in a tasty sauce and then grilled to charred perfection. These grilled watermelon "tuna" steaks have to be your new summertime favourite! They're:

Bursting With Flavour"Fish-like" In TextureSalty, Spicy, TangyAt Least CAD $10 Less ThanAhi Tuna!And An Absolute Show-Stopper!

Top down view of rectangular slices of watermelon on a baking sheet.

Baked Watermelon

I was blown away to see the texture that is created when you bake watermelon! The juices release and the watermelon tightens up creating a squishy, floppy, fish-like texture!

My first introduction to cooking watermelon was Gaz Oakley's BBQ Watermelon Fillet! Check out their recipe and video to see how they BBQ an entire watermelon!

We were inspired by Gaz's recipe and other great recipes to try a version of our own and we have had so much fun creating and enjoying these grilled watermelon "tuna" steaks!

Top down view of the fruit once baked. It's looks soft and pliable marinating in a shallow dish.

How Long Does It Take To Bake Watermelon

We slice the watermelon into 1 inch thick steaks to bring the cooking time down to 1 hour.

We have tried skipping the baking part and simply slicing the watermelon, marinating it, and grilling it. BUT, here's what happens...

Although this method still produces a tasty meal, the watermelon doesn't soak up as much marinade. It actually releases some of its juices into the marinade resulting in a less potent flavour. AND the texture of the watermelon doesn't change very much. You are left with flavoured pieces of slightly less crisp watermelon but it still tastes like watermelon to me.

Top down view of baked watermelon steaks being added to a bowl with the dark soy sauce based marinade.

Baking the watermelon for 1 hour is the key to creating a "fish-like" texture. Once the watermelon has released its own liquids it will soak up the marinade, transforming the flavour of the watermelon steaks.

*The steaks will still have a tiny bit of crispness to them which is absent in fish BUT it's a pretty impressive transformation!

*If you can't bake your watermelon, you can absolutely slice it and leave it in the marinade for a few hours or overnight. Make sure the bowl or dish you use has some extra space because the watermelon will let our more liquid. Then grill your pieces of watermelon OR remove them from the marinade and use them on a salad or fresh bowl. You will still have a tasty meal!

Ingredients For Grilled Watermelon Tuna Steaks

Since there's only two of us we've created this recipe using 1 miniature seedless watermelon.

1 mini watermelon creates enough steaks to serve 4 BUT feel free to try this with a large watermelon and increase the marinade! OR buy a couple of miniature watermelons to feed a larger group. Try cutting your watermelon into cubes for a "tuna" poke bowl!

*If your watermelon is not seedless, try and remove all the seeds prior to baking the watermelon.

Top down view of a halved watermelon. Half is sliced into rectangular strips. A few pieces are diced into cubes.

To create the flavourful marinade we use:

  • Tamari or soy sauce and miso paste for the saltiness of fish.
  • Rice vinegar and lemon juice for the tanginess.
  • Chilli garlic sauce and ginger for the peppery spice.
  • Sesame oil for the toasty Asian inspired flavour.
  • And optional seaweed for an extra taste of the ocean!
Top down view of the marinade ingredients on a white tray. Tamari, chilli garlic sauce, ginger, miso paste, sesame oil, rice vinegar, and a lemon are pictured.

How To Grill Watermelon Tuna Steaks

Grilling the marinated watermelon steaks is the last step of this show-stopper.

Again, we have tried skipping the grilling and just enjoying the watermelon steaks on our Poke Bowl, a salad, or noodles. We actually did this by accident and we were trying to figure out why the steaks weren't as flavourful. Then we realized... we had forgot to grill them! SO the moral of the story is... grilling the steaks is what really hits the flavour and texture out of the park!

Removing the steaks from the marinade and placing them on a hot grill for 3 minutes on each side:

  1. Boosts up the flavour of the marinade
  2. Adds a nice smoky, charred flavour
  3. And firms up the texture even more!
Top down view of watermelon steaks on a hot grill with grill lines seared into the fruit.

Recipe Cost

As if this couldn't get better...

This recipe serves 4 and costs us approximately: CAD $5.68 ($1.42/serving)!

VS. at least CAD $15 for the same amount of Ahi Tuna!

This recipe does take a bit more time than buying fresh or frozen ahi tuna BUT... it's so incredibly tasty, super fun and so rewarding to see how much a watermelon can transform!

Top down view of the salty, spicy, tangy marinade being whisked in a bowl with the baked steaks on a tray.

Serving Grilled Watermelon Tuna

Serve your grilled watermelon "tuna" steaks over Asian noodles and veggies, or a salad. Take a look at our Spicy "Tuna" Watermelon Poke Bowl for inspiration! The recipe for the watermelon "tuna" is exactly the same; we just cube the watermelon instead of cutting it into steaks! Get creative and let us know how you enjoy your watermelon steaks in the comments below!

Make sure to reserve the flavourful marinade and use it as a sauce for however you're enjoying your steaks! Oh and save your watermelon rind for our favourite Watermelon Rind Strawberry/Applesauce!

If you like this recipe try our popular Smoky Carrot Lox! Another thrifty fishy substitute with show-stopping looks!

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Description

These Grilled Watermelon "Tuna" Steaks are at least CAD $10 less than tuna and the fish-like texture and amazing taste will blow your mind!

Ingredients

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  • 1 mini seedless watermelon*

Marinade: 

  • ¼ cup tamari or soy sauce
  • 2 tbsp rice vinegar
  • 1 tbsp lemon juice (or lime juice)
  • 1 ½ tsp chilli garlic sauce (or hot sauce of choice, add minced garlic if you substitute)
  • 2 tbsp fresh ginger, grated or minced
  • 2 tbsp sesame oil
  • 1 tsp miso paste
  • optional: 2 seaweed snack sheets, crumbled

*Fresh ingredients you need that are not part of our pantry and freezer tips.

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Instructions

  1. Preheat your oven to 350 degrees F. 
  2. To reserve your watermelon rind for a tasty fruit sauce, slice off and discard just the green peel of the watermelon. Then slice off the thick white rind and refrigerate, freeze, or turn it into watermelon strawberry or applesauce right away! 
  3. Cut your seedless watermelon in half lengthwise, then slice each half into 1 inch thick steaks (if you want to trim the edges so you get nice rectangular steaks, cube any smaller pieces to make poke cubes!)
  4. Place the watermelon steaks in a single layer on 1 or 2 sheet pans lined with parchment paper or a silicone mat (the watermelon will let out juice that will caramelize as it bakes). Bake for 1 hour. 
  5. Meanwhile, prepare the marinade. Combine the remaining ingredients in a dish or bowl large enough to hold your watermelon steaks. *The spice in the chilli garlic sauce will get stronger the longer the watermelon marinates. If you are leaving your watermelon overnight and don’t want much heat you can decrease the amount of chilli garlic sauce.  If substituting the chilli garlic sauce with another hot sauce, add 1 clove minced garlic. To quickly grate your ginger you can leave the peel on! And If using seaweed snack sheets it’s faster to crush them by hand over the bowl but feel free to use a knife to slice them. 
  6. When the watermelon has finished baking it will be nice and soft. Transfer the slices into the marinade, making sure each piece of watermelon gets coated.  Cover the dish and marinate in the fridge for at least 2 hours. *If leaving overnight you can give the watermelon a stir periodically if you remember.
  7. When ready to serve up your watermelon steaks, heat a grill over medium heat. Lay the slices of watermelon tuna on the grill (leaving the marinade behind) and grill for 3 minutes per side until grill lines appear and the watermelon is nicely seared. Careful of splashing!
  8. If serving your steaks over rice use the tasty marinade as a sauce! Likewise, drizzle it over noodles, a salad, or roasted veggies! Take a look at our Spicy "Tuna" Watermelon Poke Bowl for inspiration! We use this same watermelon recipe but cube the pieces and drizzle spicy mayo!

Notes

Approximate Cost: CAD $5.68 vs. at least $15 for Ahi Tuna!

  • Prep Time: 25 minutes
  • Cook Time: 60 minutes
  • Category: Thrifty How-Tos
  • Method: Baked, Grilled
  • Cuisine: Asian, Hawaiian

Tag » How To Make Watermelon Tuna