The use of grated potatoes to create a crispy rosti topping turns this fish pie into something a bit special. You can use any fish really but I used two large haddock fillets which were reduced to £2.90 in Sainsbury’s. I also bought a packet of raw prawns for £3.90 – the prawns make the dish seem a bit more luxurious.

I have seen similar recipes that use a lot more ingredients and are much more complicated but I have deliberately kept this as simple as possible so that’s good value and easy to make. Leeks are so cheap and really make a difference to the flavour of the white sauce. I’m going to start using leeks more often in cooking I think. This recipe serves four people.

Ingredients

• 4 x very large Desiree potatoes
• 2 fillets of haddock or other fish (or a mixture of fish) cut into chunks
• Packet of raw prawns – preferably ready prepared with no shell and de-veined
• 2 x leeks, washed and sliced
• 50 g of butter
• 50 g white flour
• 500 ml milk (I used semi skimmed)
• Salt and pepper

Method

1. Scrub the potatoes but don’t peel them. Boil in salted water for 12 minutes, drain and allow to cool.

2.  Melt the butter in a saucepan and cook the leeks on a low heat for five minutes. Gradually add the flour and cook for another five minutes, stirring all the time. Add the milk gradually, again stirring all the time, until the sauce is quite thick. Add the haddock and the prawns (which will turn from grey to pink as they cook). Season with salt and pepper. Cook for a further two minutes.

3. Pour the fish mixture into a shallow baking dish. Peel the potatoes and grate using the coarse side of a grater. Pile the potato all over the fish mixture, add a few small knobs of butter on the potato and bake at 200 C for 25 minutes or until the rosti topping is crispy.