These little traditional fish cakes are a perfect way of using up leftover mashed potato. The fish and onion are simply cooked in stock and added to the mash with herbs. Serve with some green leaves, lemon wedges and a tartare sauce.
Sit the fish on the onion in a pan, pour over the stock, bring to a simmer, cover and cook for 8 minutes. Remove the fish. Strain out the onion, mix into the potato with the herbs. Flake in the fish, season and mix.
Shape into eight cakes, dust with flour and dip in egg, then breadcrumbs. chill for 30 minutes. Heat 1cm oil in a pan. Fry in batches for 4 minutes each side then drain on kitchen paper.