Preheat your oven to 200°C/180°C(fan)/400°F/Gas 6.
Mix 1 tablespoon Whole milk and 1 tablespoon Cornflour (corn starch) together and set aside.
Add 800 g Potato to a pan of boiling water and simmer for 12-15 minutes.
Put 250 ml Whole milk into a pan and put 240 g Salmon fillet, 220 g Smoked haddock, 150 g King prawns and 10 g Fresh parsley into it. Bring the milk to the boil and then simmer for 5 minutes.
Using a slotted spoon, lift the fish out and place in a large baking dish. Mix round so the fish flakes up.
Stir the cornflour mix and add to the milk with 130 g Sweetcorn, 1 Leek, 150 g Cream cheese and 1 pinch Sea salt and black pepper. Mix until the cream cheese melts.
Drain the potatoes and mash them with 1 teaspoon Dijon mustard and 4 tablespoon Butter.
Pour the milk mixture over the fish and stir to distribute everything evenly.
Top with the mashed potatoes and sprinkle with 100 g Cheddar cheese.
Put in the oven for 30-40 minutes. Put under the grill for 5 minutes to crisp the top.
Notes
To save time, you can buy a packet of fish pie mix from the supermarket. Just make sure that this is fully defrosted before following this recipe.
If your creamy sauce isn't thick enough, then you can add a teaspoon of cornflour to thicken it up a little.
You can make an extra crispy topping by sprinkling a mixture of panko breadcrumbs and grated cheddar on top of the mashed potato/cauliflower mix.
You could make a basic cheese sauce and use that instead.
Add some extra flavour to the sauce with a little glug of white wine.