Preheat the oven to 200C.
Wrap the fish in a piece of baking parchment & place onto a baking tray. Place the tray into the oven, & roast the fish for around 10 minutes, until the flesh has turned opaque white. Set aside to cool.
Into your food processor, add the lime juice & zest, ginger, garlic, chilli, spring onion, coriander, fish sauce, & black pepper, & run the machine until all the aromatics are thoroughly chopped & combined.
Scrape down the sides of the processor, & break up the fish into the bowl, add the potato, & pulse this all together, until the ingredients are evenly dispersed & combined.
Scoop generous tablespoons of the mixture and shape into cakes, dredge these in plain flour, & pan fry on both sides, until golden.