In a processor, pulse to a paste 250 g skinned and boned white fish fillet with ½ tsp of salt, a touch of msg (if you do) and 2 tsp of cornflour. Knead together, slapping it against the side of the bowl to knock out any air. Mould the paste into a 2cm-thick rectangular slab, then slip into the fridge, covered, to firm up. Cut into wide strips, coat each in cornflour, dip in a lightly beaten egg, then fry straight away a shallow pool of vegetable oil (a wok is good) until golden on all sides. Cool, then slice. It will reheat once it meets the dish it’s chucked in to.