In a small saucepan, bring the 1 cup dashi stock to a boil, then add the 1 teaspoon salt, ½ teaspoon soy sauce, and ½ teaspoon granulated, stirring until dissolved.
1 cup dashi stock, 1 teaspoon salt, ½ teaspoon soy sauce, ½ teaspoon granulated
Remove the pan from the heat and sprinkle on the 5 grams powdered gelatin. Stir until the gelatin is dissolved. Stir in the 1 tablespoon yuzu juice, then pour the mixture into a container and refrigerate until set.
5 grams powdered gelatin, 1 tablespoon yuzu juice
Slice the 220 grams tuna into strips, and then cut them into ½" cubes. Add it to a bowl along with the 1 teaspoon olive oil, 1 tablespoon chives, 1 tablespoon toasted sesame seeds and 2 teaspoons soy sauce. Stir to combine. Cover and refrigerate until your gelée is set.
220 grams tuna, 1 teaspoon olive oil, 1 tablespoon chives, 1 tablespoon toasted sesame seeds, 2 teaspoons soy sauce
When your ready to serve, cut the 1 avocado into cubes and sprinkle with the ½ lemon juice and a little salt. Toss to distribute evenly.
1 avocado, ½ lemon
To construct your tartare, oil a ring mold and place it in the center of a plate. Add a layer of tuna and gently pack it down.
Add a thin layer of avocado, gently packing, and then top by scooping the gelée on top like a sauce. Give the mold a few twists to make sure it's not sticking and then lift it straight up.