WATERMELON TUNA
Serves 6
Would it be possible to create delicious seared tuna without fish? That was my question because, while I love tuna, overfishing and other environmental costs mean I can’t feel good about eating it anymore. So we created this watermelon tuna instead. Locally grown watermelon is sliced into “tuna loins” and injected with Envision, an ingredient that removes sweetness and turns sweet foods savory. The watermelon is brined in seaweed-infused water and compressed in a vacuum machine to give it the texture of raw tuna. Finally, the loin is rolled in sesame seeds and briefly dropped into liquid nitrogen to achieve a seared effect around the outside of the roll. Once sliced, the watermelon perfectly resembles rare seared tuna in taste, looks, and texture. All of this is achieved at a fraction of the cost of real tuna, with zero wasteful food miles, so we can absolutely justify serving this with a good aged soy sauce seasoned with sesame and ginger.
SEAWATER:
400 grams water
15 grams salt
20 grams nori
50 grams kombu
ENVISION SOLUTION:
100 grams water
10 grams Envision Flavor and Texture Enhancer (see Sources, here)
WATERMELON TUNA:
1 small red seedless watermelon
SOY DIPPING SAUCE:
100 grams aged soy sauce
20 grams sesame oil
30 grams ginger, minced
2 garlic cloves, minced
TO FINISH:
20 grams black sesame seeds
20 grams white sesame seeds
SPECIAL EQUIPMENT:
Syringes (at least 50cc) with needles
Vacuum sealer
Liquid nitrogen (see Sources, here)
Insulated container or dewar
SEAWATER:
Put the water and salt in a medium saucepot and set over medium heat. Bring to a boil, then remove from the heat, and add the nori and kombu. Cover and steep for 15 minutes. Strain the Seawater through a fine-mesh sieve and reserve.
ENVISION SOLUTION:
Put the water and Envision in a mixing bowl and whisk to combine. Use a syringe to draw 15cc of solution for each block of watermelon. Keep cool until ready to inject into the watermelon.
WATERMELON TUNA:
Cut the top and bottom off the watermelon. Stand it up on a cutting board and use a knife to pare away the remaining skin and rind, leaving the red heart of the fruit. Square off the watermelon into a 6-by-6-by-1-inch block. Slice the block into six 6-by-1-by-1-inch blocks of watermelon. Inject each block of watermelon with 15cc of the Envision Solution, injecting it in several spots to disperse the solution evenly. This will draw the sweetness out of the fruit. Put 3 watermelon blocks in a large vacuum bag with 200 grams of Seawater and seal in a vacuum machine. Repeat with the remaining 3 blocks of watermelon. Let the watermelon rest for 1 hour in the bags at room temperature.
SOY DIPPING SAUCE:
Combine the soy, sesame oil, ginger, and garlic in a medium mixing bowl and whisk to blend. Reserve in a covered container until ready to plate.
TO FINISH:
Put the sesame seeds in a sauté pan and set over medium heat. Toast, stirring constantly, until they become fragrant and the white seeds turn golden brown, 2 to 3 minutes. Spread the sesame seeds in an even layer on a tray.
Remove the compressed watermelon from the bags and roll each log in the sesame seeds to coat.
Immediately before plating, fill an insulated container or dewar with liquid nitrogen. Drop the Watermelon Tuna pieces into the liquid nitrogen for 3 to 5 seconds to “cook” the “tuna.” Remove from the nitrogen and transfer to a cutting board. Slice ¼- to ½-inch slices of the Watermelon Tuna, crosswise. The pieces should have a white ring around a red center, resembling rare seared tuna. You will have some left over.
Place 7 slices of the “tuna” on each plate. Put 20 grams of the Soy Dipping Sauce in a small sauce bowl and place it alongside the Watermelon Tuna. Serve immediately.
