Aji Tuna Recipe

Prepare tuna

Pat the tuna steak dry with paper towels. Trim any sinew and shape into an even rectangular block about 3/4–1 inch thick so it cooks uniformly. Lightly season all sides with kosher salt and black pepper.

Coat with sesame

On a plate, combine black and white sesame seeds. Press each face and edges of the tuna into the seeds to form an even, thin crust; press firmly so seeds adhere but do not crush the tuna.

Pan-sear tuna

Heat a heavy skillet (preferably cast iron) over medium-high until very hot. Add neutral oil and swirl to coat. Place the tuna in the pan and sear 30–45 seconds per side for rare center (adjust to 60–90 seconds per side for medium-rare). Use tongs to sear the edges briefly (10–15 seconds) to set the crust. The sesame should be toasted and fragrant but the interior remain pink. Remove tuna to a cutting board and let rest 2 minutes.

Julienne cucumber

Using a mandoline or sharp knife, slice the cucumber lengthwise into thin planks, then stack and cut into 1/8-inch matchsticks (julienne). Place the cucumber in a small bowl and season lightly with a pinch of salt and a squeeze of lime; toss and let sit while you finish other components to slightly soften and release moisture.

Prepare avocado

Halve and pit the avocado. Score the flesh into 1/4-inch slices without cutting through the skin, then scoop out with a spoon and fan or slice into bite-size pieces. Toss gently with a few drops of lime to prevent browning if not serving immediately.

Sherry tomatoes

Halve the sherry tomatoes lengthwise. If you prefer a touch of sweetness, toss them with the 1 tsp dry sherry (from dressing) or a light pinch of salt and set aside.

Plate garnish

Arrange a bed of julienned cucumber on each plate, place avocado slices to one side, and scatter sherry tomato halves. Reserve microgreens or cilantro for finishing.

Make dressing

In a small bowl, whisk together mayonnaise, rice vinegar, dry sherry, wasabi, soy sauce, sesame oil, honey, and water until smooth. Taste and adjust: add more wasabi for heat, more vinegar for acidity, or a touch more honey for balance. Season with the tiny pinch of salt if needed. The dressing should be creamy, slightly tangy, with a subtle sherry note and a gentle wasabi bite.

Dress vegetables

Toss about half of the dressing with the julienned cucumber (and the tomatoes if you like) to lightly dress them. Reserve the remaining dressing to drizzle over tuna and plate.

Slice the rested sesame-crusted tuna against the grain into 1/4-inch thick slices.

Fan the tuna slices over the dressed cucumber bed and avocado. Drizzle remaining wasabi-sherry dressing over the tuna and around the plate in a decorative pattern.

Garnish with microgreens or cilantro and a light squeeze of lime. Serve immediately while tuna is warm and rare inside.