Negitoro Maki (Mashed Tuna Sushi Rolls)

Optional "shiojime" to improve flavor: Rinse 120 g sashimi grade tuna block with cold water and pat it dry with kitchen paper. Sprinkle with salt all over, then place it in a container propped up on one side to allow excess moisture to drip to the bottom. Rest in the refrigerator for 10-15 minutes, in the meantime you can prepare the rice.

Mix 2 tsp rice vinegar, 1 tsp sugar and ½ tsp salt in a bowl until dissolved.

Pour the mixture over warm 280 g cooked Japanese short-grain rice, and mix using a cut and fold motion with the edge of a rice paddle while fanning to cool. Once evenly distributed, cover the rice with a clean damp tea towel to prevent it drying out and set aside.

Wash the tuna and pat it dry with kitchen paper.

Use a spoon to scrape the tuna flesh into rough pieces.

Roughly chop it with a knife to make a chunky mash.

Transfer the mashed tuna to a bowl and add 1 tbsp Japanese mayonnaise, ½ tbsp cooking oil and ¼ tsp dashi granules. Mix until everything is combined.

Optional: Turn your gas burner on low and carefully fan 2 sheets roasted seaweed for sushi (nori) over the fire to improve the texture and aroma of the nori.

Fold the nori in half and pinch along the crease before tearing them down the fold. (Use scissors for a neater cut.)

Lay the bamboo rolling mat on a flat surface with the bamboo sticks laying horizontally. Place a piece of nori rough side facing up at the bottom of the mat.

Wet your hands and shape an 70g (approx 2.5 oz) handful of rice into a rough cylinder.

Place the rice on the nori and spread it out while leaving a finger-width border along the top. Pinch along the top edge of the rice to make a ridge, then spread wasabi through the middle.

Spread quarter of the tuna mixture through the middle of the rice, then sprinkle finely chopped green onions next to it.

Lift the bottom of the mat fold over until the rice meets.

Press firmly to shape, then lift the edge of the mat and roll once more so that the edge of the nori seals the roll.

Wipe a sharp knife with a damp cloth and cut the sushi roll in half. Use a short, sharp sawing motion to cut the roll without applying too much pressure (pressing down will squash it).

Cut each half into thirds, wiping the knife between each cut.

Enjoy with a small bowl of Japanese soy sauce (koikuchi shoyu) for dipping.