British Fish Soup: A Hearty Coastal-Style Supper Recipe

British fish soup is a comforting coastal-style bowl of flaky white fish, smoked haddock, prawns and potatoes in a gently creamy leek broth. Versions vary by region and household; this approachable one builds flavor with a little smoked fish, then keeps the broth light enough to let the seafood shine.

Ingredients

2 tablespoons (28 g) unsalted butter
1 tablespoon (15 ml) olive oil
2 large leeks (about 350 g), white and pale-green parts, washed and thinly sliced
1 medium yellow onion (about 150 g), finely diced
2 celery stalks (about 80 g), finely diced
2 tablespoons (16 g) all-purpose flour
6 cups (1.42 L) fish stock, preferably low-sodium
1½ pounds (680 g) waxy potatoes, such as Yukon Gold, cut into ½-inch (1.3 cm) cubes
1 bay leaf (1 leaf)
1 teaspoon (1 g) fresh thyme leaves, or ½ teaspoon (0.5 g) dried thyme
1½ cups (360 ml) whole milk
1 pound (450 g) skinless cod or haddock, cut into 1-inch (2.5 cm) chunks
8 ounces (225 g) smoked haddock, skin and any pin bones removed, cut into 1-inch (2.5 cm) chunks
8 ounces (225 g) peeled raw prawns, thawed if frozen
½ cup (120 ml) heavy cream
1 tablespoon (15 ml) lemon juice, plus more to taste
½ teaspoon (3 g) fine salt, plus more to taste
¼ teaspoon (0.5 g) freshly ground black pepper
¼ cup (15 g) chopped fresh flat-leaf parsley

Instructions

Prepare the ingredients, 20 minutes. Wash the leeks carefully, separating the layers enough to rinse away grit, then slice them. Dice the onion and celery, cube the potatoes, and cut the fish into similar-sized pieces so they cook evenly. Check the smoked haddock and cod for bones, and pat the raw prawns dry. Keep seafood chilled while you cook the vegetables.
Soften the aromatics, 8 minutes. Melt the butter with the olive oil in a large, heavy pot over medium heat. Add the leeks, onion and celery with a small pinch of the measured salt. Cook, stirring often, until softened and glossy but not browned, about 8 minutes. If the vegetables start sticking, lower the heat and add a spoonful of stock rather than letting the butter scorch.
Make the broth and cook the potatoes, 12 minutes. Sprinkle the flour over the vegetables and stir for 1 minute, coating them evenly. Pour in the stock gradually while stirring to smooth out lumps. Add the potatoes, bay leaf and thyme. Bring the soup just to a gentle boil, then reduce the heat and simmer uncovered for about 12 minutes, stirring once or twice, until the potatoes are nearly tender when pierced with a knife. Avoid a vigorous boil, which can make the potatoes break apart.
Add the milk and seafood, about 7 minutes. Pour in the milk and bring the broth back to a gentle simmer; do not boil it hard. Add the cod, smoked haddock and prawns, arranging them under the broth as much as possible. Simmer gently for about 5 to 7 minutes, turning the pieces once with a spoon if needed. Check the thickest fish piece with a food thermometer: fish should reach the USDA FSIS safe minimum internal temperature of 145°F (63°C). The fish should flake readily and the prawns should be opaque and firm. If a thick piece needs more time, continue simmering in short intervals and check again.
Finish and season, 3 minutes. Turn the heat to low and gently stir in the cream, lemon juice, pepper and parsley. Taste the broth before adding the remaining salt; smoked haddock and stock can already contribute plenty. Warm for about 2 to 3 minutes without letting the soup boil, remove the bay leaf, and serve while hot.

Tips

Choose fish that holds together. Cod and haddock make a familiar British-style combination because they flake into generous pieces without disappearing immediately. Pollock or hake can stand in for either white fish; they are usually a little softer, so cut them into larger chunks and handle them gently. If you cannot find smoked haddock, use an equal amount of unsmoked haddock and add a small pinch of smoked paprika. That gives a hint of smokiness but not the same savory depth, so season carefully.
Wash leeks thoroughly. Soil often collects between the layers. Slice them first, swish the pieces in a bowl of cold water, lift them out, and drain; leaving the grit behind in the bowl is more reliable than rinsing a whole leek quickly under a tap.
Keep the simmer gentle once dairy and fish go in. A rolling boil can make the fish break into tiny flakes and may cause a creamy broth to look curdled. Let the soup bubble lightly around the edges instead, and use a broad spoon to move the seafood rather than stirring vigorously.
Adjust thickness at the end. For a thicker, more filling soup, mash a few cooked potato cubes against the side of the pot and stir them back in. For a looser bowl, add warm stock a little at a time. Avoid adding cold liquid just before serving, as it drops the temperature and makes the final seasoning harder to judge.

Serving Suggestions

Serve the soup in warmed bowls with chopped parsley and a little extra black pepper. Thick slices of crusty bread, a warm roll or oatcakes are useful for catching the creamy broth; buttered bread is especially good if you want a simple, filling supper. A crisp green salad with a sharp vinaigrette can balance the richness, while steamed peas or lightly dressed cabbage make an easy vegetable side.

For a more substantial meal, offer lemon wedges at the table and let each person add a squeeze to taste. The citrus brightens the milk and cream without making the soup sour. If serving guests, keep the pot on very low heat only briefly and avoid repeated boiling; the fish is at its best while its pieces are still distinct and tender. Put out extra bread separately so it does not soak up the broth before everyone sits down.

Variations

Make it without prawns: Replace the prawns with the same weight of extra cod, haddock or pollock. The soup remains satisfying, though it loses the sweet, springy bite of shellfish. For a shellfish-free meal, check the stock label too, since some fish stocks contain shellfish or are produced alongside it.

Use a lighter finish: Replace the heavy cream with another ½ cup (120 ml) of whole milk. The soup will be less rich and slightly thinner. You can also leave out the cream entirely and finish with a little extra lemon and parsley; the flour and potatoes still give the broth some body.

Add other seafood: A few mussels or scallops can replace part of the white fish, but add them according to their size and cooking time, and check that all seafood reaches 145°F (63°C). Do not crowd the pot with too many additions, or the broth will cool and the cooking time will become uneven. Keep the total seafood amount close to the quantities listed.

Make it gluten-free: Replace the all-purpose flour with 1 tablespoon (8 g) cornstarch mixed with 2 tablespoons (30 ml) cold water. Stir this slurry into the simmering stock after the potatoes are tender, then simmer until lightly thickened before adding milk and seafood. The broth will be a little glossier and less traditionally flour-thickened. Use stock labeled gluten-free as well.

Storage and Reheating

Cool leftovers promptly and refrigerate them within 2 hours of cooking, ideally in a shallow, covered container. Keep the soup refrigerated for 3 to 4 days. Fish and prawns can become firmer after storage, so the soup is best reheated gently and served as soon as it is hot. If you expect leftovers, you can also set aside the portion you plan to store before serving to limit repeated warming.

Reheat only the amount you need in a saucepan over low to medium-low heat, stirring carefully and bringing it to 165°F (74°C), the USDA FSIS safe temperature for reheated leftovers. Check the temperature in more than one spot, especially if the soup is thick. Do not let it boil hard: once it reaches temperature, take it off the heat. A microwave also works; cover the bowl loosely, heat in short bursts, and stir gently between bursts so the center warms evenly.

For longer storage, freeze cooled soup in airtight freezer containers for up to 2 months for best quality. Dairy-based soups can separate slightly after thawing, and the fish may soften, but careful reheating and gentle stirring usually bring the broth back together. Thaw overnight in the refrigerator and reheat to 165°F (74°C). Do not thaw it on the counter or refreeze portions that have been reheated.

Frequently Asked Questions

What fish is best for British fish soup?

Cod and haddock are dependable choices: both have mild flavor, are easy to portion and form tender flakes in the broth. Smoked haddock adds a distinctive savory note that gives this version its coastal character. Pollock, hake or another firm white fish can replace the fresh cod or haddock if that is what is available.

Can I make this soup with frozen fish?

Yes. Thaw the fish and prawns in the refrigerator, then drain and pat them dry before adding them. Excess water can dilute the stock and make it harder to judge the soup’s seasoning. If you cook from frozen, the broth cools more and the seafood can cook unevenly, so thawing first is the more reliable option.

Can I prepare British fish soup ahead?

You can chop the vegetables and portion the seafood a day ahead, storing them separately in covered containers in the refrigerator. You can also cook the leek-and-potato broth in advance, chill it promptly, and add the milk, cream and seafood when reheating. This keeps the fish from sitting in hot broth and becoming overcooked before serving.

How do I stop the fish from breaking apart?

Cut the fillets into generous, even chunks and keep the broth at a gentle simmer rather than a rolling boil. Add the seafood near the end, then move it as little as possible. Use a thermometer to check the thickest piece, and remove the pot from the heat when the fish reaches 145°F (63°C); cooking far beyond that point tends to dry it out and make it fragment.

Can I leave out the smoked haddock?

Yes. Replace it with the same quantity of unsmoked white fish for a milder soup. A small pinch of smoked paprika can suggest the missing smoky flavor, but use it sparingly so it does not dominate the delicate broth. Taste before adding salt because smoked fish and stock vary in saltiness.

Why is my soup thinner than expected?

Potato varieties release different amounts of starch, and the flour measurement or simmer may also affect thickness. Mash a few potato cubes into the broth, then simmer gently for a couple of minutes and reassess. If you prefer a thicker soup, mix a teaspoon of cornstarch with cold water and stir it in gradually; let it simmer briefly before adding more.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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