Tuna Crudo Recipe

Prepare Tuna

Pat the sushi-grade ahi tuna dry with paper towels. Trim any sinew and cut into 1/4–1/3-inch slices or 1/2-inch cubes depending on presentation (slices for sashimi-style, cubes for tossed crudo). Keep chilled on a plate in the refrigerator until plating.

Season the tuna lightly with the 1/2 tsp fine sea salt and 1/4 tsp freshly ground black pepper just before plating. Sprinkle the toasted sesame seeds evenly over the pieces to add texture.

If using cucumber, arrange thin slices or ribbons on the serving plates as a base or scatter small mounds beside the tuna to add crunch.

Reserve micro basil/baby basil leaves and basil blossoms for garnish; handle blossoms gently to avoid bruising.

Make Kombu Infusion

Combine 250 ml water and 5 g kombu in a small saucepan. Let sit for 20–30 minutes at room temperature to hydrate the kombu. Slowly heat over low heat and remove the kombu just before the water reaches a simmer (do not boil).

Remove the pot from heat and let the kombu-infused water cool slightly. Add 2 cups cubed seedless watermelon to a blender with the warm kombu water. Blend until completely smooth.

Strain the blended mixture through a fine-mesh sieve or chinois into a bowl, pressing gently to extract liquid; discard solids. Whisk in 1 tablespoon light soy sauce, 1 teaspoon mirin, 1 teaspoon rice vinegar, 1/4 teaspoon kosher salt, and 1 teaspoon fresh lime juice. Taste and adjust seasoning — the dashi should be delicate, slightly sweet, and umami-driven, with a hint of acidity and salt.

Chill the watermelon dashi in the refrigerator until cold. For a clearer, more refined sauce, rest in the fridge for 30–60 minutes and skim any foam before using.

Blanch and Chill Basil

Bring a small pot of water to a boil. Prepare an ice bath. Briefly blanch the packed cup of basil leaves for 8–10 seconds in the boiling water, then immediately transfer to the ice bath to stop cooking. Drain and squeeze gently to remove excess water.

In a blender or with an immersion blender, combine the blanched basil, 1/2 cup neutral oil, a pinch (1/8 tsp) of salt, and 1/2 tsp lemon zest. Blend until bright green and smooth.

Strain the blended oil through a fine sieve or cheesecloth into a small bowl to remove any solids, pressing to extract as much oil as possible. For a very clear oil, strain twice. Store chilled until plating. If you want basil blossoms specifically infused, reserve a few blossoms and steep them in the finished oil for 10–15 minutes, then strain out—this will add floral notes.

Place tuna slices or cubes on chilled plates in your chosen arrangement (fan slices, small piles, or spaced medallions). If using cucumber, tuck ribbons or slices beneath or beside the tuna.

Spoon 2–3 tablespoons of chilled watermelon dashi around and lightly over the tuna pieces (use less for sashimi-style, more if cubes are partially marinated). The goal is a delicate coating not a pool that submerges the fish.

Using a small spoon or pipette, dot or drizzle 1–2 teaspoons of basil blossom oil over the tuna and around the plate for aromatic lift and color contrast.

Finish with a light drizzle (about 1 tsp) of extra-virgin olive oil, a pinch of finishing sea salt, and sprinkle the toasted sesame seeds if not already applied. Add a few micro basil leaves and 3–4 basil blossoms per plate. Grate the fresh lime zest over the top and add a touch of chile oil or a few thin chili slices if using for heat.

Serve immediately while the dashi and oil are cold and the tuna is chilled. This dish serves as an elegant starter; provide small spoons so diners can capture both fish and dashi in each bite.