For the risotto cube ½ of a onion and fry it in a pan with a pinch of salt. Add the vegetables broth to avoid bruning, and the stir-fry doesn´t dry.
When the onion is soft, add a cup of arborio rice. Stir and mix gently. Then add ½ cup of 120 sauvignon blanc. Simmer for 8 more minutes or until the wine has evaporated.
Bring the cup with vegetables broth to boil and slowly the rice, until you cover all the water with it. Occasionally stir.
Simmer for 15 minutes.
When the risotto is ready, take it out of the fire and add 2 tablespoons of butter, a pinch of salt, parmesan cheese and pesto tablespoons. Check the flavour, and let it rest.
For the tataki (japanese cooking method) sprinkle sesame seeds and salt on the tuna fillets, then pur them into a pre-heat pan at high heat with some olive oil drops. Seal it for both sides for 3 minutes.
When the tuna is sealed, turn the fire off and let it rest for 5 minutes before cut it into sheets.
For the bittersweet sauce, mix 2 tablespoons of balsamic vinegar, 3 tablespoons of soy soy, squeeze of a lemon, 1 tablespoon of tabasco chili sauce, 1 tablespoon of honey, 1 tablespoon of mustard, salt, and black pepper to taste.
To serve, pour a risotto portion in a dish, some tuna slices and finally some tablespoons of bittersweet sauce. Decor with chopped parsley.