There hasn’t been a time, since I’ve been cooking for myself, that I haven’t had an onion in the vegetable rack. Cheap and ubiquitous, can the onion really be regarded as a super-ingredient?
There are all sorts of reasons why it should – not least its formidable health benefits. Antioxidant and high in vitamin C, it’s widely recognised for alleviating the symptoms of colds and congestion but also plays a role in diminishing the risk of heart disease and cancer.
Onions, which belong to the allium family (shallots, leeks, chives and garlic are all related), have been cultivated for more than 5000 years. One of the earliest recorded crops, they are thought to have originated in Asia. Egyptians thought their round shape and concentric rings symbolized eternal life, and worshipped them. There is even an Egyptian onion, catalogued by the Slow Food Foundation, also known as a tree- or walking onion because of its tendency to grow to such a height that it bends over so that the onions reach the ground and take root again.
An onion is not just an onion of course; different strains differ radically in terms of size, colour and pungency. Sweet onions like Vidalia have a rating of five or less on the 10-point pyruvate scale, the official metric for onions.
Summer crops and spring onions (scallions) tend to have a higher water content and are milder than autumn-harvested ones, which are stronger, keep better and lend themselves to longer cooking times.
With very few exceptions (Jainists don’t eat them) onion use is prevalent in every major world cuisine. The French, naturally, elevated the onion and its cousin the shallot to another level, making them integral to a panoply of sauces and garnishes. Anything soubise is related to onions, but you’ll find them in everything from a béarnaise to a bordelaise or starring on their own in a meltingly sweet onion tart. No boeuf bourguignon or coq au vin would be complete without its garnish of onions; the Bordelais, with their entrecôte Bordelaise and marchand de vin, prefer the finer-flavoured shallot.
As you might expect there are official appellations for onions including the pretty pinkish Roscoff onions, borne on strings by my local Breton onion seller, but also Cebolla Fuentes de Ebro and Cippollotto Nocerino, a spring onion grown near Naples and apparently distinguished “by the softness of the bulb and the sweetness of the flesh”. On holiday I used regularly to buy Lezignan onions, which have been grown in the Languedoc since the 17th century. They could be sliced sweetly into a tomato salad and also made an excellent pissaladière, the south of France’s answer to pizza.
Onions star in English cooking too, albeit in a more homely fashion. In onion sauce and soup (creamier and milder than its darker, more intense French counterpart); studded with cloves in bread sauce; in sage and onion stuffing; sometimes even stuffed themselves. Shallots, according to Jane Grigson’s indispensable Vegetable Book, have been enjoyed since the middle ages. (Never brown them, she admonishes, or you will make them bitter – they should be slowly stewed with oil or butter).
Onions lend themselves well to deep-frying too, most popularly in onion rings (Americans apparently eat 22 pounds – roughly 10 kilos – of onions a year), bhajis and pakoras. Thai dishes often have a garnish of crisp shallots. And then of course you can eat them raw – in Mexican and Moroccan salads alike, mingled in the latter case with oranges and olives. So improbable. So delicious.
And why, you might wonder, do onions make you cry? Because cutting them releases pyruvic acid, which stimulates the tear ducts; it’s a defence mechanism against predators. Placing them in the fridge before you cut them, or chopping them under water, apparently counteracts this. But like primitive man you may just be prepared to shed the odd tear.
Three ways to use onions
1. Quick onion pickle
For an appealingly crunchy pink pickle, dissolve 1 tbsp of caster sugar and 1 1/2 tsp sea salt in just over 100ml cider vinegar, together with any flavouring spices you want to use (such as peppercorns or coriander seeds) Add a sliced red onion which you’ve blanched under running boiling water and set aside for an hour. Use immediately or keep for up to a week in the fridge.
2. Shallot tarte tatin
Shallots make the best tarte tatin, arguably even better than the apple version. You need to caramelise them (adding butter and vinegar) and cool them first before you put on the pastry lid then bake for half an hour. Cool for about 10 minutes before inverting the tart on a serving plate.
3. Onion skin stock
Onion skins, which have the same anti-inflammatory properties as the flesh, can be used to give colour and body to a vegetarian stock (just add them along with other vegetables to the stock pot. The softened skins can then be used in other recipes such as bhajis or pakoras. (They can also be used as a fabric dye should the mood take you.)
Read more from our Super-ingredient series with Fiona Beckett: