1. Prepare the Tuna

Start by selecting the freshest, sushi-grade tuna you can find. The quality of the tuna is crucial to the success of the dish, as it is the primary component. Sushi-grade tuna is typically available at specialty fish markets or high-end grocery stores and is ideal for raw preparations like tartare.

Using a sharp knife, remove the skin from the tuna and trim off any dark or fatty pieces. Cut the tuna into small, uniform cubes, roughly 1/4-inch in size. The goal is to keep the tuna’s texture intact while making it easy to eat with a fork or spoon.

2. Prepare the Flavor Base

In a medium-sized bowl, combine the sesame oil, soy sauce, rice vinegar, lemon juice, and Dijon mustard. These ingredients will create the flavorful marinade for the tuna. The sesame oil adds a rich, nutty flavor, while the soy sauce brings a savory depth, the rice vinegar offers a slight tang, and the lemon juice provides a zesty brightness. The Dijon mustard helps emulsify the mixture and adds a subtle depth of flavor.

Whisk the mixture together until fully combined and smooth. You can adjust the seasoning at this point by adding more soy sauce or lemon juice to taste.

3. Add the Tuna to the Marinade

Once the marinade is ready, add the diced tuna to the bowl. Gently toss the tuna in the marinade until it is evenly coated. Be sure not to overmix or mash the tuna, as you want to preserve the delicate texture of the fish.

Add in the finely minced shallot, capers (if using), and fresh herbs like cilantro or parsley. The shallot adds a mild onion flavor, while the capers provide a touch of brininess. The fresh herbs brighten up the dish and give it a pop of color.

If you’re using avocado, dice it into small pieces and gently fold it into the tuna mixture. The avocado adds a creamy, buttery texture that complements the tuna beautifully. For an added kick, sprinkle in a small pinch of red pepper flakes to give the dish a subtle heat.

4. Season the Tuna Tartare

Taste the tuna tartare mixture and season it with sea salt and freshly cracked black pepper. Adjust the seasoning as needed. Be cautious with the salt, as the soy sauce already adds a bit of saltiness to the dish.

At this point, the tuna tartare is ready to serve, but you can chill it in the refrigerator for about 15-20 minutes if you prefer a colder dish or want to let the flavors marinate a little longer.

5. Plate the Tuna Tartare

To serve the tuna tartare, you can use a ring mold or simply arrange it neatly on a plate. If using a mold, spoon the tuna mixture into the mold and press it down lightly to form a compact shape. Carefully lift the mold away to reveal the perfectly shaped tartare.

Alternatively, you can simply spoon the tartare onto the plate in a mound or form it into a small pile using a spoon. Garnish the dish with toasted sesame seeds, finely chopped chives, or green onions. Thinly sliced cucumber or radishes can also be added for a refreshing crunch. Serve with a wedge of lemon on the side for an extra burst of citrus.

6. Serve the Tuna Tartare

Tuna Tartare is best served immediately to preserve the freshness of the tuna and the vibrant flavors of the dish. You can pair it with crispy tortilla chips, toasted baguette slices, or cucumber rounds for a light and refreshing crunch. Alternatively, serve it alongside a simple salad or as a starter before a larger seafood meal.