Ingredients

• 8 medium baking potatoes
• 1 tbsp vegetable oil
• handful rock salt
• 1 onion
• thinly sliced
• ½ tsp black peppercorns
• 2 bay leaves
• 500g/1lb 2oz boneless
• skinless smoked haddock
• 400g/14oz haddock
• bones and skin removed
• 400g/14oz cod
• bones and skin removed
• 200g/7oz butter
• 3 heaped tablespoons plain flour
• 475ml/17fl oz milk
• 1 lemon
• zest and juice
• small bunch flatleaf parsley
• leaves roughly chopped
• 250g/9oz cooked peeled prawns
• grated cheese
• for topping
• 200g/7oz peas
• sea salt and freshly ground black pepper

Directions

• Preheat the oven to 180C/160C Fan/Gas 4.
• Prick the potatoes all over with a fork
• then rub each one with a little of the oil. Sprinkle a roasting tray with the rock salt and place the potatoes on top. Bake for 1-1½ hours
• or until tender.
• Meanwhile
• half-fill a large frying pan with water and bring to a simmer. Add the onion
• black peppercorns
• bay leaves and all of the fish
• poach for 3-4 minutes. Lift the fish from the pan using a slotted spoon
• and set aside. Strain the fish stock through a sieve suspended over a large bowl. Reserve the strained stock and discard the onion
• bay leaves and peppercorns.
• Melt 100g/3½oz of the butter in a saucepan over a medium heat. Whisk in the flour to form a smooth paste
• then cook for a further 1-2 minutes.
• Whisk in 50ml/2fl oz of the milk until it is fully incorporated into the roux. Continue to add 350ml/12fl oz of the remaining milk to the roux little by little
• whisking after each addition
• until the sauce is smooth and thick.
• Pour 750ml/25fl oz of the fish stock to the roux sauce
• stir well and cook for 4-5 minutes
• or until the sauce is smooth and just thick enough to coat the back of a spoon. Any remaining fish stock can be chilled and frozen for use in another dish.
• Stir in the lemon zest and juice
• and the parsley
• then season with salt and pepper. Remove from the heat. Stir the prawns into the sauce
• then flake in the poached fish
• keeping it in reasonably large pieces. Transfer the pie filling to a large ovenproof dish.
• When the potatoes are cooked
• remove them from the oven and increase the oven temperature to 220C/200C Fan/Gas 7.
• When the potatoes are just cool enough to handle
• slice them in half
• scoop out the flesh and pass it through a potato ricer into a pan set over a medium heat. Add 75g/2¾oz of the butter and the remaining of milk to the potatoes and beat over the heat until the mash is smooth and thick and not too soft.
• Spoon the mash into a piping bag with a large star-shaped nozzle and pipe the mashed potato all over the fish pie filling. Sprinkle over the grated cheese. Alternatively
• just spread the mashed potato onto the filling using a palette knife.
• Place the ovenproof dish onto a baking sheet and cook in the oven for 5-10 minutes
• or until the cheese and potatoes are golden-brown and the pie is heated through.
• While the fish pie heats through
• bring a pan of salted water to the boil
• add the peas and cook for 2-3 minutes
• until tender. Drain well and return to the pan
• then stir in the remaining butter and season with salt and pepper. Serve the fish pie with the peas alongside.