Here’s a seasonal question for you. When James Taylor sat down to write about the childhood sweetheart who had finally agreed to be his girl, which vegetable metaphor did he plump for?
The sweet potato. That’s right. “Oh Lord, I feel fine today,” he crooned on his 1988 album Never Die Young. “I’m walking on cloud nine today …”
Why, you ask. “I’m prepared to tell you why,” he replies. “It’s strictly on account of my sweet potato pie.”
Although few women would be delighted to be compared, however loosely, to a dish made with starchy tubers, Taylor does a decent job of selling it, and its main ingredient. It is tender, he says, it’s sweet, it’s soft and deep; it’s soulful.
If you’ve ever had a slow-roasted batch of this succulent vegetable, you’ll know he’s right. Sweet potatoes – now at the peak of their season – are the business.
They are also big business. Over the past decade, according to Kantar Worldpanel, demand for sweet potatoes in the UK has quadrupled. For a while, they mostly came from warmer climes – North Carolina, Israel – but in 2015, farmers in Kent pulled out all the stops to put a UK-grown crop in the supermarkets. That same year, the Office for National Statistics included the sweet potato in the illustrative shopping basket it uses to measure inflation. And last year, consumer research showed most people would opt for a sweet potato side dish over a straight-up potato one. Yet most of us have only begun to plumb those tender, sweet, soulful depths.
First up, sweet potatoes don’t have to be orange. Those Kentish farmers chose to cultivate the familiar red-skinned, flame-fleshed variety, often known as yams in the southern US. But if you have a Caribbean market stall or an Asian grocer nearby, you can probably get hold of something different. There are purple sweet potatoes, white sweet potatoes, yellow sweet potatoes. With the variations in colour come differences in texture, density, flavour and uses. The food website Saveur has a tantalising guide to 16 kinds, from the tan-skinned hannah, which bakes into a soft, dry yellow, perfect for mashing, to korean purple, with its white flesh and magenta exterior yielding a subtle chestnut flavour. If you can, try them all.
Sweet potato fries or baked wedges are, it would appear, the thing that has pushed the root veg into the mainstream. And it is hard to argue with them. The food writer Anna Jones recommends coating wedges in polenta before baking – it crisps them up nicely. She serves hers with a chipotle yoghurt dipping sauce. If you want to deep-fry yours, Felicity Cloake cautions that they are best thick-cut, par-boiled (with a little bicarb) and coated in a cornflour paste (she spikes hers with paprika), then rolled in cornmeal.
There is, however, more to sweet potatoes than chips. The Mississippi-born chef Brad McDonald, in his book Deep South, does a smoked pork belly served with a spiced sweet potato casserole topped with pecan praline and Italian meringue. Yotam Ottolenghi mixes them, roasted, with pickled onion, coriander and goat’s cheese as an accompaniment to fish or chicken. Vegans and “clean-eaters”, meanwhile, routinely tout the virtues of the sweet potato just as much as any meat eater.
Depending, of course, on what you load them up with, sweet potatoes are a healthier option than conventional potatoes. They are lower in carbohydrates and calories, and higher in fibre and vitamin A. Their sweetness marries with a host of aromatics – from paprika to cinnamon, thyme to cumin and coriander. And their creaminess suggests all manner of pairings: sour cream, salsa verde, miso, chilli. Nigel Slater steams slices to make a fragrant split orange lentil dal that he serves with fresh coriander. And Melissa Hemsley uses chunks as the base for a lemongrass-infused chickpea and coconut curry. Sweet potatoes also make an excellent starting point for a soup, a stew, a bake or a pie.
The traditional sweet potato pie – a Thanksgiving classic – is made with butter, flavoured with vanilla and cinnamon, encased in shortcrust and served with whipped cream. Deb Perelman of the Smitten Kitchen blog went through a southern food infatuation, as she put it, a few years back, but hankered after something a little lighter for afters. She found it in the Lee Brothers’ buttermilk sweet potato pie – more cheesecake than stodge.
Tanya Harris, of the My Forking Life blog, does a mean vegan take on the trad Jamaican sweet potato pudding using coconut milk, brown sugar and allspice, but forgoing the rum you would find in other recipes. Jamaican sweet potatoes are of the denser kind, meaning the pudding is more cake-like. But even if you only have orange jewel sweet potatoes and have to spoon the resulting bake into a bowl, it will still be delicious.
Then there are the many Japanese sweets to be made with the vegetable. The most popular is a double-baked beauty: sweet potato puree with butter, sugar, cream and egg. A scattering of black sesame seeds on top, and you’re golden.
Mostly though, it’s best to remember that the sweet potato doesn’t need much doing to it to be perfect. It is one of those culinary failsafes, a foil to every kitchen foible. There are vendors in Japan who park vans on street corners and belt out: “Ishi yaki imo”, which means stone-baked sweet potato. That is all they are selling. One bite of the piping-hot tat wrapped in newspaper and you’re sold. You’re going home to rustle up more of the same in a hot, hot oven. Slow-roasting the potato in its skin means the moisture is retained and the sugars in the skin caramelise. As savoury as it is sweet, this is a whole warming meal for cold hands on a winter’s day. And that’s something to sing about.
