Serves 6: Prep time 30 mins: cook time 25 mins
1.2kg Red-skinned potatoes, chopped into small chunks
500g undyed smoked haddock fillets
600ml whole milk
1 bay leaf
1 small Savoy or Green Cabbage, outer leaves discarded, rest finely sliced
Good grating Nutmeg
Juice 1 lemon
50g Plain Flour
50ml Double Cream
Handful fresh Parsley, finely chopped
2-3 handfuls dried Breadcrumbs
30g Strong Cheddar cheese, grated
1/Put the potatoes in a large lidded saucepan, pour over boiling water to cover, then cook on a high heat for 10-15 minutes until cooked through but not falling apart. Drain. While the potatoes are cooking, put the smoked haddock fillets skin-side down in a large lidded frying pan or sauté pan with the milk and bay leaf. Bring to a gentle simmer, cover with the lid, turn off the heat and leave to poach for 10 minutes, turning over halfway through.
2/Heat the oven to 190°C/170°C fan/gas 5. Return the cleaned potato pan to the heat and melt the butter over a medium-high heat. When the butter is sizzling, add the cabbage with a small splash of water, season and toss to coat in the butter. Put on the lid and let it steam for a few minutes until the cabbage is wilted, then remove the lid and bubble to reduce the liquid. Grate over the nutmeg and squeeze over the lemon, toss well, then stir in the flour and cook, stirring, for a couple of minutes.
3/Remove the fish fillets from the milk and set aside. Pour the poaching liquid into a jug , then gradually stir it into the cabbage – the flour will help to thicken it into a white sauce that coats the back of a spoon. Once all the poaching liquid is incorporated and the sauce has thickened, stir in the cream and parsley, then set aside.
4/When the fish is cool enough to handle, remove the skin and flake into medium chunks. Layer half the potatoes in a 1.5 litre gratin dish, then top with half the fish, then half the cabbage mix. Repeat. Scatter the breadcrumbs over the top, then the cheese, then bake for 25 minutes until bubbling, with a crisp, golden top. Leave to stand for 5 minutes, then serve with steamed seasonal vegetables.