Thai food often has loads of ingredients, but this is a stripped-down version. Use whatever white fish is fresh.
Preheat the oven to 200C/400F/Gas 6. Skin the fish and remove any bones.
Place the fish in a roasting tray and season with sea salt and drizzle with olive oil. Roast for 7-8 minutes, then remove from the oven and cool.
While the fish is roasting, prepare the flavouring ingredients. Finely chop the lime leaves.
Slice the chilli in half and remove the seeds. Finely chop.
Peel the ginger and finely chop.
Lightly crush the garlic cloves with the flat side of a knife blade, then peel and finely chop.
Bruise the lemongrass stalks with a heavy knife. Trim off the root end and discard the tough outer leaves. Finely chop.
Chop the lime leaves, chilli, ginger and lemongrass on a chopping board until all ingredients are very finely chopped.
Place the finely chopped ingredients in a large mixing bowl. Add the mashed potato and a dash of fish sauce.
Break up the cooled fish and add it to the bowl. Mix the ingredients together well.
Finely chop the coriander and add to the bowl with a squeeze of lime juice. Mix thoroughly.
Heat the vegetable oil or olive oil in a non-stick frying pan. Form the fish mixture into small cakes about 6cm-8cm/2.5in-3in wide.
Dredge the fishcakes in the flour to coat, shaking off the excess. Fry the fishcakes in the hot oil for 3-4 minutes on each side until lightly browned.
Serve the fishcakes with a squeeze of fresh lime and some sweet chilli sauce for dipping.
