Fish pie with warm tartare sauce

Preheat the oven to 180˚C/gas mark 4. Place the King Edward potatoes in the oven and cook until tender, this may take up to 90 minutes

Meanwhile, place the double cream, milk and butter into a pan and bring to the boil. Remove from the heat and set aside

Once the potatoes are tender, remove from the oven and allow to cool for 5 minutes. Peel off the skins using a small knife and then mash until all the lumps are removed — to make the mash really smooth, pass the flesh through a drum sieve or ricer

Bring the cream mixture back to the boil. Remove from the heat and add enough of the mashed potato to create a firm but smooth mix. Add the egg yolk and combine well. Season to taste with salt and cover with parchment paper. Set aside but keep warm

For the tartare sauce base, place a large saucepan over a high heat. Add the mussels, Pernod and fennel, cover and cook until the mussels have opened up. If using pre-cooked mussels, only cook for 1 minute

Remove from the heat and drain the mussels (make sure you collect the liquid), being sure to get as much stock out of the mussels as possible - the mussels are not required after this step but could be used for a hearty lunch the next day

Add the strained stock to a pan and bring to a simmer. Cook until the stock has reduced by half - it should yield 100-125ml

Meanwhile, place a pan over a medium heat and pour in the olive oil. Add the shallots and garlic and cook until tender but not coloured. Add the white wine and reduce until almost dry. Then, add the reduced mussel stock and cream to the pan

Bring the pan to a simmer and reduce slowly until it reaches the consistency of a thin sauce. Season to taste with salt and remove from the pan. Pour the contents of the pan into a blender and blend until smooth. Pass through a fine sieve into a bowl and set aside in the fridge

Preheat the oven to 180˚C/gas mark 4. Place a large, non-stick frying pan over a medium heat and add olive oil. Once the oil is hot, season the pollock fillets and place in the pan, skin-side up

Pan-fry until lightly golden, remove from the pan and then place on a lined oven tray, skin-side down. Heat in the oven for 5 minutes - or until cooked through

Reheat the mash until very hot - if the mash is not thin enough, add a dash of milk

Remove the pollock fillets from the oven but do not turn the oven off. Spoon the mash into a piping bag and then pipe over each fillet of fish. Return the pollock topped with mash back to the oven and cook for a further 5 minutes

Meanwhile, in a pan combine 120ml of the tartare sauce base, the peeled and diced plum tomato, petits pois, capers, cornichons, shallot, half a hard-boiled egg, parsley and lemon juice and zest

Bring to a gentle simmer and stir gently so that the ingredients combine

To serve, use a slotted spoon to evenly distribute the contents of the sauce into 4 large bowls. Place a piece of the pollock - topped with mashed potato - in each bowl and finish by drizzling the remainder of the sauce over the top. Serve immediately