Bring a saucepan of water to a rolling boil
Score each tomato with an X on the base
Add the tomatoes to the boiling water for 1 minute, then immediately transfer to iced water to stop them cooking
Once cooled, peel the tomatoes, cut them into quarters, and scrape out and discard the seeds
In a shallow container, mix the light soy sauce (4 tbsp), rice vinegar (1 tbsp), olive oil (2 tbsp), and sugar (1 tsp). Lay 1 nori sheet in the bottom, add the tomato pieces, making sure they are fully coated, then place the remaining nori sheet on top. Refrigerate to marinate for at least 4 hours, or overnight for the best flavour
Mix the cooked sushi rice (300g) with the rice vinegar (1 tbsp), caster sugar (2 tsp), and salt (1 pinch)
Lay 1 nori sheet shiny-side down and spread half of the sushi rice over the centre, shaping it into a square
Top with leafy lettuce, half of the tomato ‘sashimi’, avocado, carrot ribbons, sriracha mayonnaise, and the remaining sushi rice
Fold the nori over the filling, pressing firmly to seal. Repeat with the remaining ingredients to make a second onigirazu. Cut each onigirazu in half and serve
