Rinse the rice under cold water and tip into a small pan. Add 300ml boiling water and a pinch of salt. Pop on a lid, bring to the boil, then turn the heat right down and very gently simmer for 25 mins till all the water has been absorbed. Take off the heat and leave in the pan for 5-10 mins, lid on, to steam the rice.
While the rice cooks, measure out 1 tbsp of the vinegar and ½ tbsp of the sugar and mix in a bowl or dish with a pinch of salt. Halve the cucumber and set one half aside to use another day. Peel ribbons off one half with the peeler. Peel and very finely slice half the red onion. Peel and grate the ginger. Add the cucumber ribbons, red onion and half the ginger to the sugar and vinegar mix. Stir and set aside to pickle.
Mix the rest of the vinegar, sugar and ginger together. Add 2 tbsp tamari. Stir. Add the plaice fillets to the marinade and turn to coat them. Leave for 10 mins to soak up the flavours. Finely slice the cavolo nero.
Heat your grill to high. Pop the plaice fillets on a grill pan or baking tray that’s lined with foil, skinside up (keep the marinade). Grill for 4-5 mins till the plaice is cooked through and flakes easily when pressed with a fork. You don’t need to turn the fillets over – they’ll cook all the way through.
While the plaice cooks, warm a wok or deep frying pan over a high heat. Add the cavolo nero with a splash of the plaice marinade. Stir fry for 4-5 mins to just soften it a little.
Divide the rice between 2 warm bowls. Spoon over a little of the pickling liquid from the pickled veg bowl. Top with the cavolo nero and trout fillets. Serve with the pickled veg.