2 large shallots or 1 onion, peeled and chopped
2 tbsp olive oil
40 g butter
1 large thyme sprig, leaves only
4 tbsp flour
250 ml fish, chicken or vegetable stock (a stock cube is fine)
200 ml milk
4 tbsp double cream
3 tbsp chopped fresh parsley
180 g skinless salmon fillets
250 g skinless cod or haddock fillets
200 g queen scallops
150 g king prawns
1 tbsp fresh lemon juice
Sea salt and freshly ground black pepper
For the Mashed Potato Topping
750 g potatoes, peeled
75 g butter, cubed
50 ml hot milk
2 large egg yolks
75 g medium Cheddar cheese, grated
Preheat the oven to 200°C/Gas 6. Grease a shallow (about 2 litre capacity) pie dish.
Start by making the mashed potato for the topping. Chop the potatoes into chunks and cook in boiling salted water until tender. Drain well and push through a potato ricer, or mash until smooth. Add the butter and hot milk and mix until well incorporated. Allow to cool slightly, then stir in the egg yolks. Season well and put to one side.
Saute the shallots or onion in the oil and butter with the thyme leaves for about 5 minutes until softened.
Stir in the flour and cook for a minute or so. Heat the stock in a small pan or a jug in the microwave. Gradually stir it into the shallot mixture with a wooden spoon until smooth, and boil for about 5 minutes until reduced by a third. Mix in the milk, lower the heat and simmer for a few minutes. Season well, then add the cream and parsley.
Meanwhile, cut the salmon and cod into bite-sized chunks and scatter in the pie dish with the scallops and prawns. Sprinkle with the lemon juice and seasoning. Put the dish on a baking sheet.
Pour over the sauce and mix well with a fork. Spread the mashed potato on top and fluff up with a fork. Scatter with the grated cheese and put the pie immediately in the oven. Bake for 10 minutes, then turn the oven down to 180°C/Gas 4, and bake for another 20 minutes, turning if it browns unevenly. Allow to stand for 10 minutes before serving.