This is a rustic kind of soup, vaguely Greek, really more of a broth with bits. The flavour, with its bright lemon notes, is soothing and gentle rather than rich. I’ve said to add some sea bass or bream, but in truth, it would happily work with just the chunkier white fish, or a different mix. Don’t go down the oily fish route, though. Mackerel and sardines have their place, but it is not here.
2 medium onions, peeled and sliced
1 large carrot, peeled and thinly sliced
1 large bulb fennel, trimmed and finely sliced (keep the feathery fronds)
2 sticks celery, finely sliced
5 cloves garlic, peeled and thinly sliced
Fine sea salt and freshly ground black pepper
400g potatoes (preferably waxy ones), peeled and chopped into 2cm chunks
400g tin plum tomatoes, roughly chopped
1.5 litres good fish stock
200g sea bass or sea bream fillets, cut into 4cm chunks
400g other skinless white fish fillets (such as cod/pollack/hake), cut into 4cm chunks
Juice of 2 lemons
A small bunch flat leaf parsley, roughly chopped
Heat 4 tbsp oil in a large saucepan over a medium heat. Add the fennel and coriander seeds, onions, carrot, fennel, celery and garlic, plus ½ tsp salt, and sweat, stirring often, for about 10 minutes, or until the vegetables have softened, but not browned.
Stir in the tomatoes and potatoes, then add the stock and bring to a simmer. Cook for about 20 minutes until the potatoes are easily pierced to the middle. Skim off any scum from the surface periodically.
Add the fish and most of the parsley and simmer for 4-5 minutes more, or until the fish is just cooked through.
Stir in the lemon juice, check the seasoning (it will need several good grinds of black pepper, though it may not need extra salt if you used a salty readymade stock), then ladle into bowls. Add a trickle of olive oil and a sprinkling of parsley and fennel fronds to each one. Add more pepper if you feel it needs it.
Lucas Hollweg is an award-winning food writer, cookbook author and cook. A former Sunday Times journalist and cookery columnist, he writes for a wide range of food publications. His most recent book is Good Things to Eat.