Nathan Outlaw’s smoked fish pie

For the mash topping, peel the potatoes and cut into even-sized chunks. Put in a large pan of water and bring to the boil. Lower the heat to a simmer and cook for about 20 mins until tender.

Drain the potatoes and let them sit in the colander for 2-3 mins, then return them to the pan. Mash until smooth and beat in the butter and milk. Season with freshly ground black pepper and set aside.

Preheat the oven to 180C/160C Fan/Gas 4.

For the filling, dice the haddock, cut the smoked salmon into strips and cut the smoked mackerel into bite-sized pieces – make sure you remove any pin-bones. Set aside.

Heat the milk to a gentle simmer in a large pan, then turn off the heat. Melt the butter in a smaller pan and stir in the flour. Cook for a couple of minutes to make a roux, stirring continuously until it thickens, but avoid letting it turn brown. Gradually stir in the hot milk, bring to a simmer and cook the sauce over a low heat for 20 mins, stirring occasionally.

Take the pan off the heat and stir the spring onions, capers, mustard and parsley into the sauce. Season with black pepper. Add the fish and toss to combine.

Transfer the fish and sauce mixture into a large ovenproof dish. Carefully spoon the mash over the top, then scatter with the grated Parmesan.

Stand the dish on a baking tray and bake for 25-30 mins until golden on top and piping hot right through.

Serve the fish pie immediately with the steamed greens on the side.