Cook the potatoes in boiling
salted water until tender.
Drain well, return to the pan and
shake over a low heat to dry them.
Mash with 1.5 oz of the butter,
season with salt and pepper.
Melt the remaining butter for the
topping in a pan, add the leek and onion and fry gently for 5
minutes, stirring frequently.
Stir into the potato and mix well.
Place the fish in a pan, add the
milk and cook gently for 10 minutes.
Drain the cooked fish, reserving
10 fl oz of the milk.
Allow the fish to cool slightly
until cool enough to handle, then flake it, discarding the skin and
Melt the 1 oz butter in a pan,
stir in the flour and cook for 1 minute.
Gradually stir in the reserved
milk and bring to the boil, stirring, then simmer for 2 minutes.
Remove from the heat.
Stir in the flaked fish, parsley
and prawns and season to taste with salt and pepper.
Spoon the mixture into an
ovenproof dish and cover with the potato mixture, marking it in a
attractive pattern with a fork.
Sprinkle the grated Cheddar cheese
over the top.
Bake for about 40 minutes, until
the topping is golden brown, serve hot.
Substitute unsmoked fish, such as cod
or haddock, for the smoked fish or, for special occasions, salmon or
monkfish. Replace the Cheddar cheese with another brand cheese, if
preferred, or omit it altogether.