Peel and roughly chop your potatoes before boiling until cooked. Mash with with lots of butter to make a lovely creamy mash. Set to the side.
In a saucepan add a pint of milk with a bay leaf, and slowly bring to a boil. Once brought to a boil, add chunks of your favourite fish, mine are salmon, cod and smoked haddock. You'll need about 600g altogether. Turn the heat down and simmer gently for 5-6 minutes then drain off the milk carefully to avoid breaking up the fish too much, and put it to one side for later.
Melt 30g butter in a saucepan and add a good heaped tablespoon of flour. Stir to combine and cook on a low heat for 2-3 minutes. This is to cook out the flour and avoid the sauce becoming grainy. Gradually pour on the milk whilst stirring continuously until you get a smooth creamy sauce.
Add your poached fish, a handful of prawns and some chopped parsley to the sauce and fold together gently. Season to taste. Top with a really buttery mash and a sprinkling of grated cheese. Pop in the oven for 10 minutes or until golden brown.