I’m not sure there is anything in all of world cuisine better than the smell of onions gently sweating in butter. (For once I’d definitely recommend it over lard.) Even the garlic you add half-way through, just as the smell is reaching its peak, only adulterates it. I was obsessed with it when I started to cook, trying to capture and prolong it as far as possible, trying to get as much of it as I could into the finished dish. The smell is nearly complete in itself, a heady oxymoron of fat and acid, carrying both deep savoury tones and a hint of sweetness which nods towards the dark, caramel browns of onion soup, but more than anything it is the smell of possibility. Think of all of the things those onions could grow up to be! Sauces, stews, the rich juices around a roast, pilafs and pastas, hashes and frittata and fricassees – onions (I’m including their relatives) are the basis of almost everything savoury and delicious. It’s a shame that recipes mistreat them so badly. The first thing to do when looking over any recipe is to double the time it tells you to cook the onions for. I’m not sure why this is the case. Whether the length of time actually required to sweat an allium down into soft, giving delight is considered off-putting for the amateur cook, or whether it’s instinctive Masonic secrecy on the part of food professionals I don’t know, but it’s certainly irritating. If you’re making, say, a tagine, which rests on heaps of sweetly browned onions, then you’ll need to cook them for at least half an hour – and that’s if you’ve sliced them thinly.
When preparing onions for this purpose, you should always slice the (halved) onions from root to tip, and (generally) do it as finely as you can. This smashes across the structure of the vegetable, leading to quicker breakdown and cooking (slicing the ‘other’ way, across the middle in half-moons, is best for pickles and salads, when you want to maintain structure) – and more tears, unfortunately. I’ve forgotten most of the methods I’ve heard to avoid crying over your dinner. The latest was to hold a metal spoon in your mouth while you sliced, which I haven’t tried for fear of looking ridiculous. None of the tips seem to work, anyway. You get used to it after a while. Think of it as a period of mourning, if you like – weep for the onion’s brief moment of glory, bathed in gently sizzling butter, before other flavours drown out its potential – weep for the lost dreams of your own childhood. All of the things you could have grown up to be! But here you are, an adult crying hot tears over a common vegetable. To console yourself, remember that the acids which stimulate your lachrymal ducts are what make the onion so useful. You could have – you wish, for a moment, you had – chosen a large, milder Spanish one, but you went for the small brown English, and your stew will be the better for it, your cheap braising beef lulled into submission by those sharp juices.
Not that the milder ones don’t have their uses. In general, the simpler your recipe is, the milder your onion can be – and should be, in onion-centric dishes. (Cooked ones, that is – a pickled onion can be as sharp as you like). The fat Spanish example sits well in a soup or, appropriately, a tortilla, where they are one corner in a trinity of ingredients, but when you really want them to shine, the small white-skinned Italian is best of all. These are becoming increasingly available here, and are worth getting, and shaping your dinner around, when you can. You can burn them in their jackets and dress the smoked-caramel innards in pomegranate, and have them with lamb; they are excellent in place of the ubiquitous red in salads and salsas; and they are glorious cooked down en masse to form the basis of sardines agrodolce, Venetian liver, or the Neapolitan salsa Genovese (some social history in that name, which I haven’t delved into). This last, particularly, almost succeeds in capturing that essence of onion in a pan (although it also contains meat, the latter acts more as a seasoning to the vegetable, heightening the deep umami of the onion rather than the other way round) – almost, but not quite. Probably nothing can. The ancient Greeks, with a laudably scientific approach, noted the gap in savour between the smell and the taste of their sacrificial meat, and concluded that the aroma, lost with the bubbling bone marrow, went to feed the gods. Hopefully, somewhere, a small and smelly deity grows fat on the fumes of a thousand onions, and blesses us for the feast.