Preparation time40 Minutes
Cooking time20 Minutes
1Preheat the water bath to 42 degrees. Rinse the tuna steaks and rub dry. Lightly oil with olive oil. Place two tuna steaks in each bag together with a garlic clove and two sprigs of thyme and cook for 15 minutes at 42 degrees.
2Preheat the grill. Wash the cucumbers, cut into quarters lengthways and deseed. Halve the tomatoes. Lightly oil the cucumber and tomato and grill for 10 minutes on all sides. Cut into small cubes.
3Caramelize the brown sugar in a pan. Peel and finely dice the red onion and add to the sugar. Deglaze the pan with red wine vinegar. Finely chop the chili and add to the sugar mixture with the cucumbers and tomatoes.
4Add the grated lemon zest, lemon juice, bay leaf, soy sauce and hoisin sauce and let everything simmer for a few minutes. Finely chop the parsley and add to the relish.
5Remove the tuna steaks from the bags. Carefully pat dry and drizzle with a little olive oil. Season with salt and pepper. Place under a hot grill and grill on each side for 40 minutes.
6Spread out the black sesame seeds and roll the tuna steaks in the seeds.
7Slice the tuna steaks and arrange with the relish.