460 gm(2 cups) sushi rice, rinsed50 mlrice vinegar1 tspcaster sugar500 gmwhite cabbage (about ¼ small cabbage), shaved on a mandolin3spring onions, thinly sliced200 gmsmoked trout, coarsely flakedTo serve:roasted sesame seedsPickled ginger dressing100 mlgrapeseed or rice bran oil60 gmpickled ginger40 gmgolden shallots (about 2), chopped2 tsptamari2 tbsprice vinegar, or to taste
Combine rice, 600ml cold water and a pinch of salt in a saucepan, bring to the boil over high heat and cook, stirring occasionally, for 2 minutes. Cover with a lid, reduce heat to low and cook without uncovering for 8 minutes. Remove from heat. Combine vinegar and sugar in a bowl, then drizzle over rice, cover and set aside for 5 minutes. Tip rice onto a tray and spread out to cool briefly.
For pickled ginger dressing, blend oil, ginger and shallots in a small food processor, add tamari and rice vinegar and stir to combine.
Divide rice among bowls. Toss cabbage and spring onions in a bowl with pickled ginger dressing to taste, divide among bowls, top with smoked trout, scatter with extra sesame seeds and serve with remaining pickled ginger dressing.