Mark Diacono
LATIN NAME
Allium cepa
ALSO KNOWN AS
Spring onions: scallions or salad onions
SEASONALITY
Home-grown onions are harvested May–October; stored British-grown onions are available more or less all year round, sometimes with a brief gap mid-summer
MORE RECIPES
English onion soup; Roasted broccoli, red onion and cannellini salad; Lettuce and spring onion tarte tatin; French beans with shallots and black olives; Borlottis with fennel seeds and onion; Sweetcorn with spring onion, chilli and coriander; Curried new potatoes, red onion and lettuce; Roasted courgettes and onions with yoghurt dressing; Buttermilk and sage onion rings; Smashed chickpeas with preserved lemon and red onion; Squash, shallot and mushroom tart; Roast guinea fowl with onions and sage breadcrumbs; Goat kebabs with rosemary, red peppers and onion; Cider onion gravy; Bay-spiked pears with shallots and lemon; Cheddar and onion oatcakes
Onions are extraordinary. Rare is the soup, stock, stew or casserole that’s not improved by them, and a hot dog is simply not hot without smoky, sweet fried onions piled on top. How many dishes, the world over, start to take shape the moment a heap of glistening-white, chopped onion hits hot oil? The complexity of flavour tucked into the juicy layers of this humble-looking bulb – the sweetness, acidity, the deep savouriness – make it the hardest worker in the kitchen. It’s widely available all year round, largely of fine quality, and relatively inexpensive.
Onions are nutritious too, providing vitamins B, C and E, as well as a range of minerals and antioxidants. One study found that more pungent varieties of onion are richer in antioxidants, so take that as some consolation as your eyes stream over the chopping board.
Raw onions used sparingly lend a fine bite to dips, salads and even a cheese sandwich. The secret is to slice or chop them super-thin. Soaking in cold water for 20 minutes, then draining and patting dry, will also take their ferocity down a notch or two.
However, cooking reveals the full range of the onion’s characteristics. The onion plant stores its energy in the form of sugars and it also harbours harsh sulphur compounds (as a natural defence, ironically, against being eaten). Heat unlocks, mellows and blends these two elements, so that cooked onion is both richly sweet and deeply savoury, which is perhaps why it’s so versatile and well loved.
The way you handle the heat makes all the difference. Onions’ natural sugars mean that too high a temperature can result in black edges and bitterness. Start with a decent, heavy-based pan that will distribute heat evenly, and a reasonable amount of fat so the onions have something to fry in. Warm 3 tbsp olive oil in the pan over a medium heat, then add 3 finely sliced onions. A generous pinch of salt helps draw out the moisture and reduces the risk of burning. As soon as the onions start to sizzle, telling you that the heat is penetrating, reduce the heat to low and cook, stirring often.
If you put a lid on the pan, it will keep in the steam that the onions release, helping them to soften and keeping them very sweet. However, it will also reduce the extent to which they colour and caramelise – so cover them or not, depending on what you’re after. Either way, after 10 minutes you’ll get just-tender but still vibrant onions, ready for further cooking with other ingredients in any number of stews, risottos or curries; after 20–25 minutes, you’ll have a soft, sweet/sharp tangle of onions – perfect for a pizza topping or gravy. And after 40–50 minutes, you’ll have a ‘melted’, reduced, golden, silky mass for a luxurious onion soup or tart (see Pissaladière).
To make a simple onion ‘marmalade’ to go with cheese or cold meat, add 3 bay leaves or half a handful of thyme to the pan with the raw onions then, after about 30 minutes’ cooking, throw in 75g black olives, a few glugs of wine, some balsamic vinegar and a pinch of salt. Cook for a little longer to evaporate the liquid and serve warm or cold.
Frying your onions over a slightly higher heat, uncovered, until they just catch, gives them a more savoury edge that cheers sausages so famously and works so well on top of a dhal or soup.
Roasting draws out a sweetness in onions that has a fabulous, caramelised quality to it. I often throw a few quartered onions in with roasting chicken or lamb, but I roast them on their own too. Quartered (or cut into 6 wedges for larger onions), tossed in oil and generously seasoned (perhaps with a few bay leaves or sprigs of thyme added), they are perfect after about 45 minutes in the oven at 190°C/Fan 170°C/Gas 5.
However you intend to eat your onions, peeling and some form of cutting is likely to be involved, which can raise a stinging mist to the eyes and nose. Sulphenic acids are among the compounds that make onions king in the kitchen, but also the primary culprit of this discomfort. Old wives’ tales abound, but in my experience only two things help: refrigerating the onions overnight before chopping, and using a very sharp knife so that the cuts are clean without the cell-crushing that helps release those acids.
Almost all the onions in the shops have been dried for a few days, to ‘set’ the skins and increase their shelf life. You may find fresh onions – those that have just been harvested, without a period of drying – in markets, veg boxes or direct from the grower. They are a spring-into-summer treat. They have a certain liveliness that most onions lack. Often very strongly flavoured, fresh onions are best cooked gently and long.
White-skinned onions are usually the mildest, though rarest in the shops (and invariably imported). Red onions are stronger than white but sweeter too. Somewhere between an onion and a shallot in strength, they’re a great choice for serving raw. Red onions also tend to retain their structure more than other onions: even long, slow cooking won’t melt them to the same silkiness as white or yellow onions. This trait has its uses though, especially in onion tarts and when baking onions whole. Yellow (actually brown) onions are the most common, and almost always the most strongly flavoured. Whatever colour or size, look for onions that are firm and unbruised. They are best stored in cool darkness if you’re not using them quickly.
Onions can be grown from seed or sets (mini onions), sown in early spring. I don’t grow many though, as yellow/brown varieties are relatively inexpensive in the shops, and I can’t hope to grow anything like the number I use. Any space I dedicate to this vegetable is for a few lines of red onions.
There are, however, various other long-stemmed, bobble-headed, oniony plants out there, often looking rather like giant chives, that are incredibly easy to grow. Welsh onions give you a kind of spring onion, as well as edible flowers, while many of the perennial onions (including Egyptian walking onions) will give you a few harvests, including some or all of the following: chive-like stems early in the season, with any you leave unharvested becoming like spring onions, in time forming mini shallots at the top of their stems, with the bulbs at the base swelling into small shallots too.
Shallots
Shallots are very special. Growing in clusters at the soil’s surface, and wrapped in their own bronze paper, they are more subtle in flavour than onions and more approachable when raw (though you should still prepare for running eyes when chopping). Use them when just a little oniony-ness is required – raw in dressings where vinegar tempers any harshness, or lightly cooked in sauces.
Large, torpedo-shaped eschalot and echalion shallots, also known as ‘banana shallots’, are my favourites. Their easy sweetness is perfectly balanced by plenty of oniony edge and there’s less fiddle in peeling and chopping than with smaller shallots.
Roasted and caramelised whole, shallots are fabulous with fish and meat – beef especially. Peel half a kilo (or as many as you fancy) and toss them in 2 tbsp sugar before adding to an ovenproof pan over a high heat. Allow them to caramelise for a few minutes, shaking the pan frequently so they don’t burn. Add a large knob of butter and a dash of olive oil, then transfer the pan to the oven at 190°C/Fan 170°C/Gas 5 for 15–25 minutes, until the shallots are tender.
Thin, fleshy and with a tight pale bulb topped with hollow green leaves, spring onions carry a pretty potent kick, but one that is somehow more agreeable than raw onion. Thinly sliced, they brighten up many a dressing, soup, salad or stir-fry. If push came to shove, I’d even probably prefer an onion bhaji made with spring onions to one fashioned from normal onions. Best of all, spring onions take to the barbecue or griddle brilliantly. Peel off the outer layer, cut off the roots and coat the shaft in a little olive oil before they hit the heat. Allow 2–3 minutes each side, until softened and browned. A yoghurty garlic dressing sets them off beautifully.
Few dishes celebrate onions – and the divine, silky sweetness they can achieve – better than this Provençal classic. A sort of thickly onioned pizza, it uses piquant, salty anchovies and olives to offset the onions’ richness. Serves 4–6
FOR THE DOUGH
125g plain white flour, plus extra to dust
125g strong white bread flour
1 level tsp fine sea salt
½ tsp fast-acting dried yeast
1 tbsp olive oil, plus extra for oiling
FOR THE TOPPING
3 tbsp olive oil
1kg onions, halved and very thinly sliced
3 garlic cloves, finely sliced
8–10 anchovy fillets in oil
About 75g pitted black olives
2 tsp baby capers, drained and rinsed (optional)
1 tbsp thyme leaves
Sea salt and black pepper
TO FINISH
Extra virgin olive oil, or the oil from the anchovies
To make the dough, combine the flours, salt and yeast in a large bowl, add 160ml warm water and the oil, and mix to a rough dough. Turn out on to a lightly floured surface and knead for about 10 minutes, until silky and elastic.
Put the dough into a lightly oiled bowl, cover with cling film and leave in a warm place to rise for 1–2 hours, until doubled in size.
Meanwhile, make the topping. Heat the oil in a large frying pan over a medium heat. Add the onions and a good pinch of salt. When they start to sizzle, turn the heat right down, partially cover the pan and cook very gently, stirring occasionally, for about 50 minutes or until the onions are very soft, golden and translucent, but not browned. Stir in the garlic, cook for a minute or two more, then remove from the heat.
Preheat the oven to 220°C/Fan 200°C/Gas 7 and lightly oil a shallow baking tin, about 21 x 30cm.
Tip the dough out on to a well-floured surface. Pat it very roughly into a rectangle with your fingers then roll it out until it’s big enough to fit the prepared tin.
Lift the dough into the tin, pressing it up the sides a little to create a rim. Spread the softened onions over the dough. Arrange the anchovies in a lattice pattern on top and place the olives, capers, if using, and thyme in between.
Grind over some pepper and bake for 20–25 minutes, until the crust is slightly browned and the onions are catching in places. Trickle over a little extra virgin olive oil or oil from the anchovy tin/jar for a more intense anchovy flavour. Serve hot, warm or cold.
