This recipe is a combination of traditional mashed-potato topped fish pie and dauphinoise potatoes, with some extra vegetables thrown in because I throw extra vegetables into everything. I used whiting, but any other sustainable white fish such as pouting can be used; similarly the cuttlefish balls (which I found in the local Chinese supermarket) can be substituted out for any other shellfish depending on what’s available.
Gently heat 400ml milk in a non-stick frying pan with 1/2 diced onion, 4 cloves, 2 bay leaves and a pinch of salt. Once the milk is steaming, tip in a large handful of Brussels sprouts, peeled and halved, and about half of a small sweet potato, cut into 1 cm cubes. Poach until beginning to soften, then add 200g whiting, cut into 1 inch slices, and 4-5 cuttlefish balls, cut into eighths. Once the fish is cooked through, lift everything out of the milk with a slotted spoon (or use a sieve) and place in a large casserole dish. Stir in 1/3 cup sweetcorn and 1/3 cup edamame beans or peas.
Return the milk to the heat and add 3-4 medium potatoes, peeled and sliced very thinly (ideally ~1 mm); add extra milk to cover if necessary. Poach, occasionally stirring to make sure they don’t stick together, until they are just cooked through. Lift the potatoes out of the milk and layer over the fish mixture.
Pour the milk into a jug, stir in 1/4 teaspoon nutmeg and 1 tablespoon of cream if desired, and set aside. Wipe down the inside of the frying pan, then melt 25 g butter over a medium heat. Mix 2 tablespoons flour into the butter and cook for 1-2 minutes or until the roux is dark golden in colour. Pour the milk into the frying pan in increments, making sure that the mixture is well combined before adding more. Continue adding milk until a white sauce consistency is reached – this should take all the milk in the jug, and might need more. Season the sauce with salt and black pepper, then pour over the potatoes, making sure that it soaks through into the fish mixture.
Bake the pie in the oven at 180°C for 35 minutes, or until the potatoes are easily broken with a fork and the top of the pie is golden-brown.
Serves four, suitable for freezing.