Sustainable fish pie

Had salmon for supper recently? If so you are not alone, a recent survey showed that salmon is the UK’s most popular fish dish. Salmon is good for us but our love of salmon puts pressure on our ocean.

The salmon on your dinner plate is probably farmed, around 60% of the world’s salmon production is farmed, and in Scotland this figure reaches 100%, with the last commercial wild salmon fishery closing in late 2018. Farming salmon at an industrial scale requires large quantities of feed including wild caught fish. The current quantity of wild fish fed to farmed Scottish salmon, 460,000 tonnes, is roughly equivalent to the amount purchased by the entire UK population.

In February, we are asking you to swap salmon for something a bit different – turns out there is plenty more (interesting) fish in the sea.

Keenan Humble is the development chef of the Alchemic Kitchen, a Feedback social enterprise working alchemy with surplus food. He has created a recipe for a fish pie that uses some often overlooked fish such as herring and whiting. These fish are sometimes fed to farmed salmon but we think they are good enough for us to eat!

For the topping

1.5kg potatoes (peeled and chopped)
75g butter
Dash of milk
50g finely grated hard cheese.

For the filling

1 large onion (diced)
1 leek (diced)
750ml milk
1 bay leaf
200g frozen peas
600g fillets of kippers or herring, depending on whether you want a smoked flavour or not
800g whiting fillets (deboned and cut into 2cm cubes)
75g butter, plus a little extra for frying
75g all-purpose flour
½ bunch parsley (chopped)
Salt & pepper
3 eggs (hard boiled & sliced)

1) Boil the potatoes until cooked through. Drain, then leave to steam in a cullender. You still want to mash them when they are warm but this will allow them to dry out a little, giving you light, fluffy mash. Mash the potato with the butter and a dash of milk and leave to one side.

2) For the filling, put a knob of butter into a saucepan and add the onion and leek until they are softened, pour over the milk, add the bay leaf, salt and pepper and frozen peas and bring to simmering point.

3) Once the milk is simmering (not boiling), add the kipper fillets and cook until the fish starts to flake. Remove the kippers at this point and set to one side, allowing to cool slightly, before picking the meat away from the skin and discarding any bones.

4) Add the whiting into the milk, and cook until they are not quite flaking, the fish will continue cooking in the oven.

5) Strain the milk mixture through a sieve (saving the milk in a jug or bowl), remove the bay leaf and put the whiting, onion and leek into an over proof dish with the flaked kipper fillets.

6) In the saucepan that you poached the fish, add the butter and melt over a medium heat, before pouring in the flour. Stir this constantly to make a smooth paste in the pan, you do not want to colour the paste but you need to cook the flour for a minute or so. Gradually add the infused milk, now whisking to ensure the sauce remains smooth. If the sauce does start to split, or is too lumpy, take it off the heat and stir like crazy until it is saved.

7) Add the parsley to the sauce and pour over the fish in the oven proof dish. Place the sliced boiled eggs in a layer over the fish and sauce before topping with mashed potato. Spread this evenly over the top of the filling and run a fork over the top of the surface (this will create some lovely crispy bits on the surface of the pie). Sprinkle with grated cheese of choice, I would probably go with a nice cheddar and plenty of cracked black pepper.

8) Bake in the oven for 40 minutes at 200C/180C Fan/Gas Mark 6 until the top is golden and crisp.