Step 1

Cook the potatoes in a saucepan of boiling, salted water for 15-20 minutes or until tender. Drain well, mash and set aside, covered.

Step 2

Meanwhile, preheat the grill to medium-high. Put the haddock in a roasting tin and brush with 1 tablespoon oil. Grill for 8-10 minutes or until just cooked through. Set aside to cool, then discard the skin and bones and flake into chunks.

Step 3

Gently fold the haddock, capers, lemon zest, parsley and egg yolk into the mash, and season. Shape the mixture into 8 fishcakes and cover and chill for 20 minutes or overnight.

Step 4

Meanwhile, spoon the mayo into a bowl. Mix in the horseradish, lemon juice, salt and pepper to taste. Cover and chill until needed.

Step 5

Heat the remaining olive oil in a frying pan over a medium heat. Dust the fishcakes with a little flour and fry for 3-4 minutes each side, until golden. Serve 2 per person with the horseradish mayo, lemon wedges and a mixed salad, if you like.