Instruction

• Put the potatoes in a large pan of cold salted water and bring to the boil
• Lower the heat, cover, then simmer gently for 15 minutes until tender
• Drain, then return to the pan over a low heat for 30 seconds to drive off any excess water
• Mash with 1 tbsp olive oil, then season
• 02
• Meanwhile put the milk in a large sauté pan, add the fish and bring to the boil
• Remove from the heat, cover and stand for 3 minutes
• Remove the fish (reserving the milk) and pat dry with kitchen paper, then gently flake into an ovenproof dish, discarding the skin and any bones
• 03
• Heat the remaining oil in a pan, stir in the flour and cook for 30 seconds
• Gradually stir in 200-250ml of the reserved milk (discard the rest)
• Grate in nutmeg, season, then bubble until thick
• Stir in the cream
• 04
• Preheat the oven to 190°C/fan170°C/gas 5
• Grate the artichokes and add to the dish with the leek, prawns and herbs
• Stir the lemon zest and juice into the sauce, then pour over
• Mix gently with a wooden spoon
• 05
• Spoon the mash onto the fish mixture, then use a fork to make peaks, which will crisp and brown as it cooks
• Sprinkle over the cheese, then bake for 35-40 minutes until golden and bubbling
• Serve with wilted greens