The oniony tang of leeks perks up many dishes, and keeps your eyes and bones on top form
The homely leek is a biddable, accommodating vegetable, but the cooking method is critical. An encounter with leek that's squeakily undercooked can be quite offputting, and apart from soups, where the thinly sliced green flags add a characteristic whiff and bright colour, leeks are generally best kept away from water.
Fried leeks make a crisp, interesting garnish for bowls of Asian noodles or simple risottos. Cook them down slowly with butter and they swoon into a fondant state, while developing a savoury sweetness. At which point, they can bring another layer of flavour and a gooey thickness to ingredients such as ham, cheese, potato and pasta, or served as a bed of puree under grilled sausages and fish.
Why are leeks good for me?
Leeks contain significant amounts of the flavonoid kaempferol. Many studies suggest it reduces the risk of developing chronic diseases – cancer in particular. It also appears to support our cardiovascular system by protecting our blood vessel linings.
Leeks are an excellent source of vitamin A, which aids vision and supports the immune system, and bone-building vitamin K and manganese. They also contain vitamin B6, which appears to reduce homocysteine in the blood; elevated levels of this amino acid are associated with a greater risk of heart disease, blood clots and strokes.
Where to buy and what to pay
Leeks are best bought whole, or lightly trimmed, for freshness. Ready chopped leeks cost around twice as much as trimmed leeks, while baby leeks come in at an eye-watering £13.50/kg. Guide price for whole/trimmed leeks: £2.70/kg.
Leeks, olives and manchego on toast
This is a sort of less cheesy, more substantial cheese on toast. Leeks go splendidly with most cheese, but particularly well with the more citrussy acid flavours one finds in sheep and goats' cheeses.
600g leeks, trimmed of their roots and as little green top as possible, cut into 5cm pieces and washed thoroughly
3 tbsp olive oil
1½ tbsp water
4 sprigs thyme
2 tbsp black olives, pitted and roughly chopped
1 tbsp dijon mustard
120g manchego, coarsely grated
4 slices of good bread
1 garlic clove, cut in half
Salt and pepper
1 Heat a large pan with a lid and add the leeks, olive oil, water and thyme. Stir well to coat with the oily water, and season a little. Cover and cook over a medium heat for about 10 minutes until the leeks are very tender. Shake the pan or stir occasionally to make sure they aren't sticking, adding more water to stop the pan from going dry before the leeks soften. Meanwhile, preheat the grill.
2 Once the leeks are cooked, stir in the olives and mustard and finally the cheese.
3 Toast the bread lightly on both sides and rub one side with the cut side of the garlic clove. Pile the leek mix on to the bread and put under the grill until the cheese is melting, and the mixture is bubbling and starting to brown. Serve straight away with some salad.
Rosie Sykes is head chef of Fitzbillies (fitzbillies.com) and co-author of The Kitchen Revolution (Ebury Press, £25). To order a copy for £19.99 with free UK p&p, go to theguardian.com/bookshop
This will be Joanna and Rosie's final column for the present. Look out for our new feature, Storecupboard Challenge, next week
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