Spiced sweet potato soup

Giving the vegetables a quick blast in the oven adds some serious depth to this simple, versatile soup.


In my student days I lived in an enormous shared house where there always seemed to be a huge vat of pumpkin soup on the stove, ready to supply instant gratification at any time of the day or night. Life was more chaotic then – or, at least, it was a different brand of chaos – and having something warm, substantial and comforting to eat provided us with a rare moment of domestic calm.

The habit has stayed with me, although the soup itself has evolved over the years into something more vividly orange and more adventurously flavoured, available on demand from stovetop, fridge or freezer.

Sweet potatoes produce a gorgeous soup and even more so when they, and the carrots that complement them so well, are given a quick blast in a hot oven. They won’t cook through – far from it – but it’s enough to develop their sugars just enough to give the finished soup a real depth.

The spices in question are the ying and yang of the spice rack, cumin and coriander, and ground ginger. The dried chilli flakes provide what I think is a necessary tingle of heat, always welcome to perk up potentially stodgy food, though you can wind them down or omit them altogether if chilli is not on your agenda.

An immersion or stick blender makes quick work of this. If you’re going the blender route, remember that blending hot liquids builds up pressure, so work in batches and cover the hole in the lid lightly with a wadded-up tea towel to avoid a soupy explosion across your kitchen walls.

Spiced sweet potato soup


Serves 4.

1 large sweet potato, about 500g (1 pound)
2 large carrots, about 250g (½ pound)
1 shallot or small onion
2 cloves garlic
1 teaspoon olive oil
½ teaspoon each of ground cumin, ground coriander, ground ginger and dried chilli flakes
1 litre (4 cups) vegetable stock
100g (½ cup) red lentils
sea salt flakes
freshly ground black pepper

Set your oven to 220°C (425°F). Cut the sweet potato and carrots into similar sized chunks and place on a baking tray. Cut the onion into quarters and add to the tray, along with the peeled whole cloves of garlic. Drizzle with a little olive oil and toss with your hands. Roast for about 20 minutes, or until the very first signs of colour are starting to develop.

Warm a teaspoon of olive oil in a large, heavy based saucepan over medium heat. Add the roasted onion pieces and garlic. Stir in the cumin, coriander, ginger and chilli flakes (if using), cooking just until they become warm and fragrant.

Add the sweet potato, carrot and lentils and pour over the stock. Bringing up to a boil and reduce to low, letting it simmer, uncovered, for 30 minutes.

Puree the soup with an immersion or regular blender (see note above). Taste, seasoning with salt and pepper as required. Serve with a cooling dollop of unflavoured Greek-style yoghurt.

The soup can be refrigerated and reheated as required, and it freezes very well, too.