Tuna, sea bass and trout nigiri and British tuna rolls

Method

1. To make the sushi vinegar, put the rice vinegar, sugar and salt in a saucepan over a low heat. Heat gently to 50C, stirring with a whisk.

2. Remove from the heat and continue stirring until the sugar and salt have dissolved.

3. Add the kombu and leave to infuse overnight at room temperature.

4. To make the sushi rice, put the rice in a large bowl and cover with cold water. Gently swirl the rice with your hand, then drain immediately. Repeat two or three times, until the water becomes clearer.

5. Drain off as much water as possible. Gently rub the rice between your hands in a circular motion to remove any remaining bran.

6. Add fresh water, swirl and drain again. Repeat until the water is no longer cloudy.

7. Tip the rice into a colander and leave to drain for 10–15 minutes. Tilt the colander slightly to help any excess water drain away.

8. Put 450ml/15fl oz water in a saucepan with a lid and gently add the washed rice. Leave to soak at room temperature for 30 minutes to 2 hours.

9. Cover the pan with the lid and put over a high heat. Bring to the boil, until steam begins to escape.

10. Reduce the heat to low and simmer for 10 minutes.

11. Turn off the heat and leave the rice, covered, for another 10 minutes to steam. Don't lift the lid during cooking or steaming.

12. Remove the lid and gently fluff the rice with a rice paddle or spatula.

13. Transfer the rice to a wooden sushi rice tub or large bowl. Drizzle over the sushi vinegar and gently fold it through the rice using a rice paddle or spatula, taking care not to crush the grains.

14. Fan the rice until it's warm, then cover with a damp cloth until needed.

15. To make the tsukuri soy sauce, put the soy sauce, sake, mirin and kombu in a saucepan over a medium heat. Bring gently to the boil.

16. Add the bonito flakes, reduce the heat and simmer gently for 3 minutes.

17. Remove from the heat and leave to cool.

18. Strain through a fine sieve lined with kitchen paper.

19. To make the nigiri sushi, mix a little water with a splash of sushi vinegar to make tezu, a mixture used to stop the rice sticking to your hands. Keep the sushi rice, fish and wasabi nearby, along with a damp cloth for wiping your hands and knife.

20. For the soy-cured tuna nigiri, lightly cure the tuna in soy sauce. Using a sharp knife, slice against the grain into pieces about 7–8cm/2¾–3¼in long, 2.5–3cm/1–1¼in wide and 5mm/¼in thick. Use one long pulling motion for each slice.

21. For the sea bass nigiri, slice the ike-jime sea bass against the grain into pieces of the same size.

22. For the trout nigiri, lightly cure the ike-jime trout with salt and sugar. Slice against the grain into pieces of the same size.

23. Lightly wet your hands with the tezu. Shape 15–20g/½–¾oz rice into a small oval for each nigiri, taking care not to squash the grains.

24. For the tuna nigiri, put a slice of tuna in your palm and spread a little wasabi over it. Put the shaped rice on top.

25. For the sea bass nigiri, put a slice of sea bass in your palm. Add a small piece of shiso leaf and a little yuzu kosho, then put the rice on top. Finish with a little freshly grated yuzu zest.

26. For the trout nigiri, put a slice of trout in your palm and spread a little wasabi over it. Put the rice on top.

27. Gently press the rice onto the fish, then turn the nigiri over. Shape it with two fingers so the fish sits neatly over the rice.

28. Finish the tuna and trout nigiri with a little tsukuri soy sauce.

29. To make the tuna sushi rolls, cut the tuna into batons about 10cm/4in long and 8–9mm/⅜in square.

30. Put a sheet of nori, shiny-side down, on a sushi mat, with the long edge facing you.

31. Lightly wet your hands with tezu and spread 90g/3¼oz rice evenly over the nori, leaving a 1.5cm/⅝in strip uncovered along the far edge.

32. Spread a thin line of wasabi across the centre of the rice. Arrange four tuna batons in a two-by-two square, alternating the different cuts of tuna to create a chequerboard pattern.

33. Lift the near edge of the mat and roll it over the filling, holding the tuna in position with your fingertips. Press gently, then continue rolling to seal the nori.

34. Gently press the roll through the mat to make a neat square shape. Leave seam-side down for 1 minute.

35. Using a sharp knife wiped with a damp cloth, cut the roll in half, then cut each half into three pieces. Wipe the knife between cuts.

36. Repeat with the remaining ingredients.

37. Arrange the nigiri and tuna sushi rolls on serving plates with the pickled ginger. Serve with the tsukuri soy sauce.