• 110 g onions
• 3 or 4 slices of carrot
• 1 small bay leaf
• a sprig of thyme
• 3 peppercorns
• 600 ml milk
• 170 g sliced mushrooms
• butter for frying
• salt and freshly ground pepper
• generous 1 kg fillets of cod haddock, ling hake or pollock or a mixture
• 30 g roux
• a very little cream (optional)
• 2 tablespoons chopped parsley
• 4 hard-boiled eggs
• 18 cooked mussels (optional)
• 900 g Duchesse potato or soft mashed potato

Accompaniment

• Maître d’hôtel butter or garlic butter (optional)

Put the onions, carrot, bay leaf, thyme and peppercorns into the milk, bring to the boil and simmer for 3–4 minutes. Remove from the heat and leave to infuse for 10–15 minutes. Strain.

Meanwhile, sauté the sliced mushrooms in a little butter in a hot pan, season with salt and freshly ground pepper and set aside.

Put the fish into a wide pan or frying pan and cover with the flavoured milk. Season with salt and freshly ground pepper. Cover and simmer gently until the fish is cooked. Take out the fish, carefully removing any bones or skin. Bring the liquid to the boil and thicken with roux; add a little cream (optional) and the chopped parsley, roughly chopped hardboiled eggs, mushrooms, pieces of fish and the mussels. Stir gently, taste and correct the seasoning. Spoon into 1 large or 6–8 small dishes and pipe Duchesse potato on top. The pie may be prepared ahead to this point.

Put into a moderate oven 180°C/350°F/Gas 4 to reheat and slightly brown the potato on top, 10–15 minutes if the filling and potato are warm, or about 30 minutes if reheating the dish from cold.

Serve with garlic butter or maître d’hôtel butter. For garlic butter just add 2 large crushed cloves to the recipe for maître d’hôtel butter, and omit the lemon juice.