Photo: Dan Jones
Cook the potatoes in boiling salted water for 12-15 minutes until tender. Drain, mash with the butter and season, then set aside to cool.
Meanwhile, preheat the oven to 200°C/gas mark 6. Grease a large sheet of foil with butter and place the haddock in the middle. Top with the bay leaves and some seasoning. Fold the foil over and scrunch
the edges together to form a loose parcel. Put on a baking tray and bake for 12-15 minutes or until the fish is just cooked. Unwrap the foil and leave to cool slightly.
Add the prawns, chives and mustard to the potato and mix well to combine. Discard the bay leaves, then flake the haddock into large chunks. Gently stir into the mash so you don’t break up the fish too much. Shape into 6 large balls and poke a hole in the middle of each with your thumb. Cut the cheese into six even cubes and press a piece into each hole, then shape the fishcake around to encase.
Lightly dust the fishcakes all over with flour. Dip into the beaten egg, then coat in the breadcrumbs. Place on a lined baking tray and chill in the fridge for 15 minutes to firm up.
Heat the oil in a large frying pan and fry the fishcakes on both sides for 2-3 minutes until golden. Transfer to a baking tray and bake for 15-20 minutes until piping hot.