Why a One-Pot Fish Stew Belongs in a Coastal Kitchen

There is a particular kind of cold that only arrives on the coast. It comes in off the water sideways, gets under the door, and settles in the bones long before the heating has caught up. On evenings like that you want something that simmers quietly on the hob, fills the kitchen with steam, and asks almost nothing of you at the end of the day.

This fish stew is that dish. It uses affordable white fish, a couple of leeks, a few potatoes, and herbs that are already in the cupboard. Everything happens in one heavy pot, which means one hob ring, one wooden spoon, and one washing-up bowl at the end. For a household of four it costs very little, and it tastes far grander than the effort involved.

Choosing the Fish: Cheap, Sustainable and Full of Flavour

You want roughly 600g of boneless white fish to serve four generously. The good news is that the cheaper end of the fishmonger's slab is often the tastiest. Firm-fleshed options include:

• Pollack or coley — both excellent value and hold their shape well
• Whiting — delicate, sweet, and usually the cheapest thing on offer
• Haddock or hake — a little pricier, but beautifully silky in a broth
• Ling or monkfish trimmings — ask what is going cheap that day

Frozen fillets work perfectly well here. Defrost them overnight in the fridge, Pat them dry with kitchen paper, and cut them into large chunks — roughly the size of a matchbox. Small pieces will disintegrate, so keep them chunky. If your fishmonger sells offcuts, cheeks or bellies, snap them up; they are ideal for a stew and cost a fraction of neat fillets.

One rule worth keeping: buy the fish on the day you plan to cook it if you can, and keep it cold on the way home.

The Supporting Cast: Potatoes, Leeks and Cupboard Herbs

For four people, gather the following:

• 1 large onion or 2 banana shallots, sliced
• 2 medium leeks, white and pale green parts only, sliced and washed thoroughly
• 500g waxy potatoes, peeled and cut into 2cm cubes
• 2 garlic cloves, finely sliced
• 1 heaped teaspoon smoked paprika
• 2 bay leaves and 4 sprigs of thyme (or 1 teaspoon dried thyme)
• 400ml fish or vegetable stock, made from a cube is fine
• 200ml whole milk, plus a splash of double cream to finish
• 1 tablespoon plain flour
• Butter and a little olive or rapeseed oil
• Salt, black pepper, a lemon, and a handful of flat-leaf parsley

Waxy potatoes matter more than you might think. Floury varieties break down and turn the broth cloudy and gluey, which is not what you want. Leeks should be sliced, then swirled in a bowl of cold water so any grit sinks to the bottom before you lift them out.

Method: Building the Stew in One Pot

Step one. Set a large casserole or heavy-based saucepan over a medium heat. Add a knob of butter and a glug of oil, then tip in the onion and leeks with a good pinch of salt. Cook gently for eight to ten minutes until soft and sweet, not browned.

Step two. Stir in the garlic and smoked paprika and cook for one minute until fragrant. Sprinkle over the flour and stir for another minute — this thickens the broth slightly and stops it tasting thin.

Step three. Pour in the stock a little at a time, stirring to keep it smooth. Add the potatoes, bay leaves and thyme, bring to a gentle simmer, then cover and cook for 12 to 15 minutes until the potatoes are nearly tender.

Step four. Pour in the milk and let it come back to a bare simmer. Taste and season. Now lay the fish chunks on top of the potatoes rather than stirring them in — they will poach in the steam and stay whole. Cover and cook for 5 to 6 minutes, no more.

Step five. Take the pot off the heat. Stir in a spoonful of double cream, a squeeze of lemon and most of the chopped parsley. Let it sit for two minutes before serving.

Finishing Touches and What to Serve Alongside

Never boil the stew once the fish has gone in, or it will break apart into shreds. If you want it thicker, lift out a few potatoes and mash them back in rather than reducing the liquid hard.

Serve it in wide bowls with thick slices of buttered crusty bread, or a warm soda bread if you have made one that day. A green salad dressed sharply with lemon cuts through the cream beautifully. For a coastal touch, a scatter of chopped dill instead of parsley works just as well, particularly with haddock or hake.

Making It Ahead and Using Up What Is Left

The base — everything up to the point the fish goes in — can be made a day ahead and kept in the fridge. Bring it back to a simmer, then add the fish and finish as normal. It also freezes well before the milk and cream go in.

Leftovers keep for two days in the fridge, though the potatoes will soften further and the fish will flake. Reheat very gently in a pan with a splash of milk, stirring as little as possible. If it has broken down completely, turn it into a fish pie filling: tip it into a dish, top with mashed potato, and bake at 200°C (180°C fan, gas mark 6) for 25 minutes. Nothing wasted, and a second supper for almost no extra work.