Creamy fish gratin

serves 8
ingredients
100g/4oz butter
175g/6oz leeks, roughly chopped
450ml/3⁄4pt fish stock
300ml/10fl oz vermouth
4 tablespoons Pernod
350g/12oz monkfish fillet, cut into
large pieces
350g/12oz salmon fillet, cut into
large pieces
225g/8oz raw prawns, peeled
and deveined
225g/8oz raw scallops, halved
175g/6oz onions, chopped
100g/4oz plain flour
150ml/5fl oz double cream
450ml/3⁄4pt milk
75g/3oz Parmesan cheese, grated
75g/3oz Gruyère cheese, grated
1 tablespoon Dijon mustard
4 eggs, separated
15g/1⁄2oz coarse breadcrumbs
salt and ground black pepper

• Preheat the oven to 190°C/375°F/Gas mark 5.
• Melt 25g/1oz of the butter in a pan. Add the leeks and cook, stirring,
for 4–5 minutes until golden. Pour in the stock, vermouth and Pernod,
and bring to the boil. Add the monkfish and salmon, and simmer for
2–3 minutes, then add the prawns and scallops, and simmer for another
3 minutes. Remove the fish, reserve the liquor and wipe out the pan.
• Add 50g/2oz of the butter and the onions to the pan, and cook for
10 minutes or until soft and golden. Stir in 50g/2oz of the flour, and
cook for a further minute, stirring. Pour in the reserved poaching liquor
and the cream, whisking to prevent lumps forming. Bring to the boil and
bubble hard for 10 minutes. Season with salt and pepper. Put the fish
and leeks in a 2.4-litre/4pt ovenproof dish, then pour the hot sauce over
the top.
• Melt the remaining butter in a large pan, add the remaining flour and
cook, stirring, for 1 minute. Pour in the milk and, whisking continuously,
bring the mixture to the boil. Stir in 100g/4oz of the cheeses and the
mustard. Cool slightly, then stir in the egg yolks. Season well.
• Whisk the egg whites in a bowl until they form soft peaks, then fold them
into the sauce. Spoon the topping over the fish, and sprinkle with the
remaining cheeses and the breadcrumbs. Cook for 1 hour and serve hot.