• 600 ml/20 fl oz full-fat milk
• ½ small onion, thinly sliced
• 6 black peppercorns
• 1 bay leaf
• 2 fresh parsley stalks
• blade of mace
• 300 g/10½ oz undyed smoked haddock
• 115 g/4 oz cod fillets
• 150 ml/5 fl oz dry white wine

Tabasco

• 175 g/6 oz small cooked prawns, shelled
• 1 small pot (about 55 g/2 oz) potted shrimps
• 24 uncooked queen scallops, about 200 g/7 oz (optional)
• big pinch of finely chopped flat-leaf parsley

For the Mash

• 1.3 kg/3 lb Maris Piper potatoes, scrubbed
• sea salt and freshly ground black pepper
• 6 tablespoons full-fat milk
• 50 g/1¾ oz butter, plus 25 g/1 oz to dot on top

For the Béchamel Sauce

• 50 g/1¾ oz butter
• 50 g/1¾ oz plain flour
• 2 tablespoons double cream
• white pepper

To make the mash, put the potatoes in a big pan of salted water, bring to the boil, then simmer for 20–25 minutes, until a knife goes through with ease. Tip into a colander, let them cool down a little, then peel. Heat the milk and butter in a small saucepan until the butter melts, then mash the potatoes with the milk. Season.

Preheat the oven to 180°C/350°F/Gas 4. Put the milk, onion, peppercorns, bay leaf, parsley stalks and mace in a large shallow pan, heat to a simmer and then poach the smoked haddock and cod for 5–6 minutes, until the fish just flakes when pressed with a knife. Lift out the fish, remove the skin and any stray bones and set aside. Strain the milk through a sieve into a measuring jug; discard the flavourings. If necessary, add a little extra milk to make up to 600 ml/20 fl oz; set aside.

To make the béchamel sauce, melt the butter in a saucepan over a low heat, stir in the flour using a wooden spoon, and cook for 2–3 minutes; do not let it brown. Remove from the heat and slowly stir in the reserved milk until smooth. Add the cream and cook for 2–3 minutes, adding salt and white pepper to taste.

Add the wine to the béchamel and cook gently, stirring, for a further 2–3 minutes. Add a big dash of Tabasco. Add the fish, shellfish and chopped parsley and put into a pie dish.

Cover the fish mixture with the mash; using a fork, fluff up the top into small waves and dot with a little extra butter. Put in the oven for 20–30 minutes, until the top is golden.