Usually relegated to a base or a stock, the humble leek has a unique, subtle flavour and can be the star of the show in many recipes, says Russell Brown
Leeks are one ingredient that form the base of so much cooking. A key ingredient in mirepoix, they can truly be called a building block in the culinary armoury. How many dishes do not in some way owe at least a degree of their complexity to the leek? Chefs use leeks all year round, but they really come into their own between November and April, and it is perhaps at this time of year that they are more likely to be centre stage rather than in a supporting role.
Leeks have been cultivated since ancient Egypt and were first introduced into the UK by the Romans. They are part of the allium family and as such are related to onions, garlic, shallots, etc.
Leeks were reputedly favoured by Roman emperor Nero, who believed they improved singing, and they are also the national emblem of Wales. It is uncertain whether this is a tribute to St David or because a seventh-century Welsh army used leeks in their hats to identify themselves in a battle against the Saxons.
A typical growing season would see leek seeds being drilled from late February to early May. Many fields are hand-weeded and successional sowing, along with the use of fleece blankets to cover early crops, significantly extends the length of the growing season.
Most commercial production in the UK is centred around Cambridgeshire, Lincolnshire, Nottinghamshire and Northumberland.
Classic leek recipes would include vichyssoise, leeks au gratin and leeks à la crème; modern use, however, is much more varied, from boiling to chargrilling to techniques such as barbecuing and sous vide. Leek terrines, crumbles, pies, risottos, soups and chowders are all common.
Leeks find favour across the globe, too. In Belgium they are used in flamiche, a pie containing slowly-stewed leeks mixed with egg yolk; in Turkey, leek leaves are stuffed with a rice-based mix to make sarma, and in Sri Lanka thel dhala is a side dish of leeks fried with chilli and garlic. They also feature in a Sri Lankan curry with potatoes, spiced with turmeric, chilli and curry leaves. Leek ash has also been seen frequently in recent years, where leeks are charred in a hot
oven, allowed to dry out completely and then ground to a powder, which adds bitter, smoky notes to dishes.
Bristol-based private chef and event caterer Tara Clist suggests braising leeks in red wine and chicken stock or stewing them with fennel seeds and olive oil. Guy Owen at the Idle Rocks in St Mawes, Cornwall, butter-poaches leeks then bakes them with goats’ cheese as an accompaniment to lamb, and chef David Mooney sweats leeks with bacon and then bakes with an aged Emmental sauce.
Buying and storage tips
- Store leeks untrimmed if possible.
- Keep refrigerated in sealed boxes to preserve moisture and contain odour.
- Buy leeks with as much white/pale green as possible.
- Tops and outside leaves are excellent for stocks.
- Leeks often contain sand or soil, so split the top half lengthwise, fan out the leaves and wash thoroughly, or wash after slicing.
- Fresh leeks should keep for up to two weeks if refrigerated.
UK leek season runs from September to April. It used to be a lot shorter, but modern varieties have extended it. Expect to pay £1.20 to £1.50 a kilo.
Buttered leeks and crab on toast
400g trimmed leeks, sliced 1cm thick
50g unsalted butter
Maldon sea salt and freshly ground black pepper
30g crème fraîche
1tsp Dijon mustard
Lemon juice to taste
150g white crab meat, picked
4 slices sourdough bread
1 clove garlic
20g Parmesan shavings
Sweat the leeks gently in the butter with a pinch of salt, cooking until just tender. Add the crème fraîche, mustard and season to taste with the lemon juice, sea salt and black pepper. Fold in the crab meat and warm through.
Drizzle the slices of bread with olive oil and chargrill. Once cooked, rub lightly with the garlic clove.
Place the bread on the plates and divide the crab and leek mix between the slices. Scatter over the Parmesan shavings as desired and sprinkle the paprika on top. Drizzle with some good extra virgin olive oil and serve.
Leek and Gruyère tarts with leek vinaigrette
Serves 8 as a starter
For the tart
450g rough puff pastry
25ml olive oil
1 small onion, finely diced
White of 2 medium leeks, halved lengthwise and finely sliced
4 large free-range egg yolks plus 2 whole eggs
80g double cream
10g Dijon mustard
140g Gruyère, grated
Green centres of the leek tops sliced into rings/lozenges and chargrilled
Maldon salt and freshly ground black pepper
For the leek vinaigrette garnish
1 medium leek, trimmed
2tbs classic mustard vinaigrette
Maldon sea salt and freshly ground black pepper
1tsp chives, chopped
1tbs hard-boiled egg, chopped
Start by making the pastry cases. Roll out the puff pastry into a rectangle around 3mm thick. Brush with water and roll up like a Swiss roll. Cut into eight, press in from the ends to compress a little into rough discs. Chill for 10 minutes. Roll out the pastry into a circle just big enough to line 10cm individual tart tins. Prick the base of the pastry cases with a fork and chill again. Blind bake at 160°C for 15-20 minutes, then remove the baking beans and cook for another 10 minutes until the pastry is just golden.
Sweat off the onion and leek white in the olive oil with a pinch of salt. Cook until completely tender and then allow to cool.
To make the filling, mix the egg yolks, eggs and double cream together, whisk in the mustard and then season. Stir in the cheese and the onion/leek mix. Pour into the cases and then top with rounds of chargrilled leek. Bake at 160°C for 25-30 minutes until golden and just set. Serve warm.
For the leek vinaigrette, cook the leek in simmering salted water or vegetable stock until completely tender. Drain and allow to cool. Press out any excess moisture. Slice into 1cm rings and dress with the vinaigrette and season. Divide between the plates and sprinkle over the chives and egg. Place the warm leek tarts to one side.