Ingredients:
200g smoked halibut
200g salmon
400g fish cream
250g mashed potatoes (or enough to cover the pie)
20g grated parmesan

For the mash
1kg Maris piper potatoes
200g butter
50ml milk
1 egg yolk

For the fish cream
50g butter
50g flour
500ml milk
1 bay leaf
½ onion
1 garlic clove
The skin from the smoked halibut
English mustard
A hand full of parsley

Method:

Bring the milk, garlic, haddock skin, onion and bay leaf to the boil and leave to infuse for 20 minutes.
Melt the butter in a heavy-bottomed pan, then add the flour and cook until it is light brown and sandy in texture.
Slowly add the milk, beating constantly a bit at a time. Cook for 20 minutes on a low heat.
Finish with mustard and parsley; season to taste.

For the mash

Peel and boil the potatoes in salted water until they are soft enough to fall off a sharp knife, and then pass using a fine sieve or mouli. Fold in the butter, egg yolk and milk season to taste.

To finish the pie

Cover the bottom of a baking dish with the fish cream. On top of that put the salmon and halibut. Cover the fish generously with more fish cream. Top with the mashed potato and grated parmesan. Bake for 20 mins at 200C.

Recipe adapted from The Telegraph.