Leeks.

The most delicate and digestible member of the Onion Family, leeks are one of few vegetables native to Europe.

Wonderfully versatile, they can be used to both add flavour to other vegetables or in their own right, as an accompaniment or a preparation for a dish.

Cultivated for over 3000 years and held in very high esteem by the Egyptians, leeks are rich in vitamin A and C, as well as iron and magnesium, and well-suited to lowering cholesterol. The Romans believed leeks to impart sonority of the voice and Nero supposedly had leek soup served to him every day to ensure the clear delivery of his orations. In other historical accounts – unrelated, of course – the Romans extolled this hardy vegetable for its aphrodisiacal properties.

Indeed, the most “vegetal” and earthy specie of the allium genus, the “hardest working family in the food business”, (Leiths Cookery)  the leek is one of the Forbidden Five Buddhist monks are instructed to renounce, on the basis that they “excite the senses”. Ubiquitous but indispensable, this is a highly regarded family in culinary circles, a prominent pillar of the vegetable variety with countless applications. The metaphor of having as many layers as an onion probably fits nothing more aptly than the onion itself. 

Described as offering a “creamy combination of onion and cabbage flavours” by the Flavour Thesaurus, leeks make an especially good partner for gentle yet flavourful meats such as pork, veal and lamb, and similarly vegetables: ranging from potatoes to asparagus, as well as dairy: from soft creams to hard cheeses.

“Look for firm, white leeks with lively green leaves” is the advice from the Italian culinary bible, the Silver Spoon. Mrs Beaton goes further: “with a good ratio of white to green”. Both undoubtedly very sensible pieces of advice. 

Although commercially available all year round, their best period is in the colder months, from the end of Autumn to early Spring: and at their most delicious in late Winter. 

PREPARATION:

Cut off the green parts and trim the base. Remove outer layer and rinse thoroughly. It is often the case that the white part goes up further than you had thought, so it is advisable to slit beneath the first green leaf layer before cutting off the green parts.

Some chefs are in favour of using the green shoots also; like the Swiss Chard, the key is to separate the greens from the whites and treat them differently. 

COOKING:

Delicious baked or boiled, most usually leeks are smothered with melted butter and cheese. The Italians advocate the generous boil – as they often do with vegetables – for up to 15 minutes. The English, forever haunted by over-boiled vegetables of childhood side on security, preferring them to be slightly resistant in the middle: “but only slightly”, warm instructions from Jane Grigson, whose scholarly endevours trace the deep-rooted aversion back to Mrs Beeton, who over 150 years ago steered the nation and thus set in motion many a child’s early horrors to over-boil leeks, so as “not to taint the breath”.

As other Onion Family members, slow sweating or soaking takes away harshness and induces their natural sweetness. A decidedly delicious, all-purpose method is to gently cook them in a heavy-bottomed pan, with half-butter and half olive oil: sweating them for a couple of minutes on medium heat, then adding a small splash of water, covering with a lid and cooking until they soften and combine to make a gentle, melting mixture. Seasoned with salt towards the end of the cooking they will hold their own next to any accompaniment as a fully upstanding side dish. And even make a full meal, paired with a poached or fried egg. 

The most prudent piece of advice of all - again from Ms. Grigson: “Watch them”.

USE:

Leeks share some similarities with other delicate-tasting vegetables such as fennel, Swiss chard and cauliflower, as well as some more flavourful, spring vegetables such as peas, artichokes and asparagus - indeed, they are sometimes referred to as ‘the poor man’s Asparagus’. And as such, they share preparations common to these groups: 

They are sumptuous served warm with hollandaise (which should be room temperature); they pair perfectly with potato as well as egg and ham; they can even be sliced thinly and eaten raw in a salad; they are superb in pastry, in a simple quiche, tart or pie, flan or a timbale; and they make a fine frittata or risotto, finished with parmesan and single cream instead of the habitual butter. 

A most exalting way with leeks is a gratin – a dish in which they are quite unsurpassed by any other vegetable (- the closest contender might be fennel, potatoes for this purpose excluded). This is an excellent mid-week supper or a lightly sustaining lunch; -

In the French way: baked with a beachamel sauce flavoured with Gruyere and topped with Parmesan, potentially with the addition of cooked ham if you are so inclined.

Or the Italian way: with a bechamel  flavoured with Ementhal, nutmeg and a beaten egg yolk, baked sprinkled with Parmesan and breadcrumbs. 

A bulkier gratin can include potatoes: slice the leeks and potatoes and make alternate layers in a buttered oven dish; bring a pan of double cream to boil with a pinch of salt and a clove of garlic. Once the cream is thickened discard the garlic, pour over the dish, and bake for half an hour covered with grated Parmesan.

Young leeks are most delicious cooked and eaten cold, with a vinaigrette – plain, of Dijon mustard and white wine vinegar - or more jazzed up with capers, parsley, shallots and chives. Some add a splash of water to the viagrette, and others grate over a hard-boiled egg.

They can also be char-grilled, for a very appetizing accompaniment.

Soups are a well-established way with leeks, familiar to many cultures and of innumerable iterations: high-brow/low-brow, hot/cold, creamed/clear, the leek soup’s winning streak is that it has a preparation for any amount of weather, season and budget – and can be paired with almost any a course. Poshly called the potage Parmentier, the commonplace leek and potato soup is traceable to the French courts. Its cold cousin, the Vichyssoise, dates to 1917 and was coined so in the US. The familiar ingredients are: leeks, potatoes, onions, chicken stock, cream – sometimes milk – white pepper. The more contested include: nutmeg, chives, garlic, parsley and white wine.

Here is an recipe from the grand master of French cuisine, M. Escoffier, ‘the King of Chefs and Chef of Kings’, for the original soupe a la bonne femme. Translated as housewife soup, intending leek soup, in its initial incarnation a clear soup of leek and potatoes: leeks are sautéed in butter, covered with water and then the potato added. Just before serving more butter is added, and this mixture poured into a tureen in which has been put some thin slices of French bread dried in the oven. Thoroughly enjoyable in the company of plenty open space.

Leeks are also highly enjoyable in hearty soups: an ancient German leek and barley soup is made with chicken stock, cream and flavoured with nutmeg, and like many old soup recipes is thickened with an egg yolk at the end.

Or the traditional, Scottish Cock-a-Leekie – made with leeks, chicken stock and prunes.  

 The most excitement-making soup however is the Five Onion Soup (garlic, onion, spring onion, leek and chive soup): the full Forbidden Five out of bounds to those faithful Buddhist monks. 

British baking traditions employ leeks just as hardily as the French with their quiches and tarts: in addition to short-crust pies of leek and chicken, leek and ham or leek and hake (St John), savoury Eccles cakes are delicious made with Stilton and leeks, as are scones with cheddar or Wensleydale and leeks.

As a side dish, leeks work well cooked in white wine – a method that also works well with broccoli, and indeed the two are delicious paired together in this method: parboiled, then combined in a pan with (or without) tomatoes, completed with (or without) cream, finished in the oven (or not), topped with parmesan (or not.): there are multiple possibilities to express and experiment yourself here.  

Some grand leek recipes with wine - 

The Dutchess of Devoshire’s Leeks in Mustard Sauce (leeks sweated, simmered with wine and cooked covered, finished with cream, mustard, tarragon and chives)

Fortnum and Mason Creamed Leeks with Crispy Bacon (leeks sweated, simmered in wine and completed with cream and thyme; topped with crispy bacon)

More forgiving - 

The Silver Spoon’s Leeks and Tomatoes (leeks are parboiled and then simmered covered with a tomato mixture of tomatoes, garlic, wine, thyme to finish)

My personal preference for everyday is for either wine or cream, rather than both. When using cream, vegetables are delicious cooked first in stock, which contributes an earthy depth rather than the added headiness of wine: moisten leeks with a small amount of stock and top off with a dash of the richest double cream. This can be done with other greens such as peas, lettuces, broad beans and is delicious in some combination of these also.

As a flavouring, some Italian chefs favour leeks when making a more gentle sofrito; and all advocate the inclusion of a leek in stock, especially of chicken or vegetables.  

Lastly – but of course not leastly – leeks make a delectable sauce for pork or veal chops: soften in a pan with butter, sprinkle with flour and add stock, cooking for further 10 minutes. Pass through a sieve into a clean pan and finish with lemon juice, double cream, parsley, salt and white pepper. 

When it comes to those top green shoots, some favour employing them in soups or bakes, eliminating just a couple of centimetres at the top; or simply boiling and dressing with olive oil and herbs or spices as a side dish. The leaves can also be used as an outer layer for neat parcels stuffed with meat or cheese, as would be cabbage leaves.

Go well with:

Tomatoes, asparagus, broccoli, peas, fennel, avocado, potato

Hard cheeses, blue cheeses, cream, butter

Most meats, especially chicken, veal, pork, and lamb, ham, bacon; mushrooms, egg

White fish, especially cod; salmon

Sage, nutmeg