Leeks have been synonymous with Wales since, according to legend, 640AD, when King Cadwallader and his men, locked in battle with invading Saxons, wore them to identify each other and won a great victory. But, if you imagined acres and acres of leeks all over Wales, you would be wrong.

In fact, until recently, very few were grown commercially there at all – most hailed from Lincolnshire. That is, until a bunch of Wales-loving Englishmen, including farmer Andy Blair, set up the Really Welsh Trading Company in Llantwit Major, with a mission to restore leeks to their spiritual home and grow them “plumper, juicier and sexier than ever”.

“Now, we’re pulling up 40 tonnes a week. Leeks are much loved here, but people weren’t aware that they were mostly being grown elsewhere,” says Really Welsh’s Richard Arnold, who is from Wales. “Ours have bigger flags [the green parts] and look less like batons and more like a kid’s picture of a leek, with a very distinct bottom, middle and top.”

Because they like a deep, rich, cold silt-loam soil rather than the shallow, warm soils of south Wales, where Really Welsh is based, its leeks are grown in the north of the country, in Queensferry, Flintshire, and are sold locally in Waitrose and in Tesco stores around the UK.

When are they in season?
Really Welsh harvests from September to March. “The flavour will vary from subtle to more intense during the season, so Easter leeks will taste different to the earlier, thinner, stringier ones,” says Arnold.

What’s the best way to use them?
“A leek can be used for anything you’d use an onion for,” says Arnold. “But it’s a bit more subtle and rounded in flavour. As well as in soups and stews, you can stir-fry them, or sauté them and toss with lemon juice and thyme, or roast them in olive oil, or serve them raw, finely chopped with vinaigrette in a salad.”

Having said that, one of his favourite traditional recipes is for cawl cennin, a lamb and vegetable broth. Cennin is Welsh for leek and Cennin aur is used for that other national emblem, the daffodil, also grown by Really Welsh, as a challenge to the primarily Cornish and Dutch market.

To make enough cawl for eight, cut the white parts of 500g leeks into four lengthwise, then chop roughly, along with a head of celery and 100g onions. Chop the green parts finely and set aside. Fry the white parts and other vegetables in 25g melted butter for a few minutes without browning. Add 2.5 litres vegetable stock, bring to the boil, then simmer for an hour, skimming as necessary. Liquidise, then reheat, stirring in the chopped green leeks and some cubes of cooked lamb. Season to taste and serve garnished with a swirl of double cream and some chopped parsley.

Readers’ queries

I tasted some Webster’s Stilton at Christmas. Where can I buy it?

The smallest of the Stilton dairies, Webster’s (Main Street, Saxelby, near Melton Mowbray; 01664 812223) doesn’t offer mail order, but you can buy in person, or mail order from Brocklesby Farm Shop in nearby Asfordby (01664 813200; www.brocklebys.co.uk).

If you have a food query, e-mail food.detective@thetimes.co.uk

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