Sarah's Superfoods: Sweet potato recipes
The recipes in this article first appeared in Country Living in May 2015.
As a nation, we’re devoted to potatoes, eaten every which way. But why not use more of the healthy, coral-orange sweet potato? I make a dish similar to dauphinoise potatoes, with sweet potato, coconut, ginger and lime, which has the same comforting texture, yet a much greater nutritional value. The same is true of soup: swap cream-laden vichyssoise for my super-healthy, saffron-coloured sweet potato, carrot and peanut butter recipe. It’s one of my favourites.
The sweet potato is a great source of fibre and vitamins, particularly C and B6. Also, like carrots, the orange fleshed varieties are packed with an orange pigment called beta-carotene (in the family of carotenoids). The deeper the orange, the greater the density of the pigments; sweet potatoes have the highest level, followed by carrots, and other orange and yellow fruit and vegetables, such as squash, melon, peppers and apricots. Surprisingly, the dark, leafy greens kale and spinach also have high concentrations.
Beta-carotene aids night-time vision, is anti-inflammatory and appears to help the immune system. However, most importantly, diets rich in carotenoid-dense foods (beta-carotene included) can help to prevent cancer. A large study at Harvard University showed a 32 percent reduction in the risk of lung cancer in those who consumed more carotenoid-rich foods as part of their regular diet, compared with those who ate less. Another study of women (conducted by Women’s Healthy Eating and Living), who had completed treatment for early-stage breast cancer, found that those with the highest blood concentrations of carotenoids (from a diet generally high in these fruit and vegetables) had the least likelihood of cancer recurrence.
Sweet potato is a carbohydrate-rich food that releases its natural sugars slowly into the bloodstream (particularly helpful to anyone with type 2 diabetes), whereas a white bread sandwich or standard baked potato causes a rapid sugar spike in our blood (owing to their high glycaemic index, or GI). When boiled or steamed, sweet potatoes have a reasonably low GI of 46, compared to 82 if they are roasted and 94 if they’re baked. White bread has a GI of 70; normal jacket potatoes of 69 with skin, or 98 with no skin, so steamed sweet potatoes are slow in their sugar release by comparison. Incidentally, carotenoids are a fat-soluble vitamin, so always eat them with a little fat, such as olive oil or coconut milk, or combine them with nuts to aid absorption. If you buy organic varieties, you can eat the flesh and skin; otherwise peel before eating, as the skin may have been treated with dye or wax. Then drop them into a bowl of water to prevent the flesh oxidising in the air.
Native to Central and South America, sweet potatoes aren’t frost-hardy and need a long growing season with plenty of light, so they are probably a vegetable to buy rather than grow. It’s now, in mid spring, when fresh, local, seasonal vegetables are hard to find, that they should rise to the top of the shopping list.
This article includes four recipes:
- Sweet potatoes with coconut, ginger and lime
- Sweet potato, carrot and peanut butter soup
- Sweet potato tagliata with watercress, ginger and soy
- Adzuki bean and root vegetable chilli
SWEET POTATOES WITH COCONUT, GINGER AND LIME
Preparation 15 minutes. Cooking 1 hour 20 minutes.
Enjoy this with a green salad or serve alongside sea bass or salmon and a salsa verde or ginger, chilli and coriander sauce. If eating as a main dish, top with pomegranate seeds for extra crunch and goodness.
Serves 4-5 as a main or 6-8 as a starter
- 1.5kg (4-5) small-medium sweet potatoes
- 100g piece fresh ginger
- 1 red chilli, deseeded and finely chopped
- 3 garlic cloves, peeled and crushed
- 400ml tin full-fat coconut milk
- juice and zest of 2 limes
- 2 heaped tbsp runny honey or maple syrup (optional)
- seeds of a pomegranate (optional)
Heat the oven to 180°C (160°C fan oven) / gas mark 4.
Peel and cut the sweet potatoes into 1-2cm rounds and put in a large bowl.
Peel the ginger with a teaspoon. Finely chop it, with the chilli and garlic – I do this in a food processor. Add the coconut milk, lime juice and zest, honey or maple syrup (if using) and blitz briefly.
Pour over and mix well with the sweet potatoes – your hands are best for this. If making double or triple quantities, increase the coconut milk, lime, honey, garlic, ginger and chilli by only 50% to the proportions of the sweet potato, otherwise the dish turns into a soup. Season with flaky salt and freshly ground black pepper.
Transfer the mixture to a 21cm x 28cm casserole or baking dish. Cover with a lid or foil and bake for 1 hour until the potatoes are tender. Uncover and bake for an additional 15-20 minutes until the top is browned. Scatter with pomegranate seeds (if using).
SWEET POTATO, CARROT AND PEANUT BUTTER SOUP
Preparation 30 minutes. Cooking 40 minutes.
Health credentials aside, this is one of my favourite fragrant soups, with a strong taste of peanut butter. The ginger cuts through the richness of the nuts and sweet potato.
Serves 6 as a main or 8-10 as a starter
For the peanut butter (makes 500ml)
- 500g unsalted peanuts
For the soup
- 2 tbsp olive oil
- 1 large onion (about 200g), roughly chopped
- 2 garlic cloves, finely chopped
- 1 red finger chilli, seeds removed and finely chopped
- 2 lemongrass stalks, outer leaves removed and sliced
- 5 tbsp fresh ginger, grated
- 800g sweet potatoes, peeled and roughly chopped
- 3 large carrots (about 300g), peeled and roughly chopped
- 1 litre hot vegetable stock
- 1 x 400ml tin coconut milk
- 2 heaped tbsp peanut butter
- dried, flaked seaweed or mineral salt and freshly ground black pepper
- handful of fresh coriander, roughly chopped
- handful of roasted unsalted peanuts, roughly chopped
- lime wedges
First make the peanut butter. Heat the oven to 180°C (160°C fan oven) / gas mark 4. Put the peanuts in a single layer on a baking tray and roast in the oven for 20 minutes until golden brown. Leave to cool.
Put the peanuts into a food processor and blitz for about 5 minutes for a crunchy version or longer for a smooth one.
Heat the olive oil over a medium heat in a heavy-based pan. Add the onion, garlic, chilli, lemongrass and ginger, and sauté until the onion is soft.
Add the sweet potato, carrots and stock, and bring to the boil. Turn down the heat and simmer gently for 10-15 minutes until the sweet potato is soft. The carrots will be a little firmer.
Allow to cool slightly, pour into a food processor and blitz for 10 seconds, keeping texture to the vegetables.
Pour the soup into a large pan, adding the coconut milk and peanut butter. Stir over a medium heat but don’t boil. Season to taste.
Ladle the soup into bowls and serve with the fresh coriander, roasted peanuts and lime wedges in separate dishes.
SWEET POTATO TAGLIATA WITH WATERCRESS, GINGER AND SOY
Preparation 20 minutes. Cooking 25 minutes.
In this recipe, sweet potato slices are steamed and briefly griddled, which is better for your blood sugar levels than roasting. They are then dressed in a little olive oil and served on a bed of punchy-tasting, colourful leaves.
Serves 4 as a main or 8-10 as a starter
- 1kg pink-flesh sweet potatoes
- a little rapeseed or coconut oil, for frying
- 250g (4 large handfuls) of mixed peppery salad leaves, such as watercress, mizuna, rocket or any of the mustards and chicory
- 1 large handful of coriander (about 30g), leaves and stems coarsely chopped
- 2 heaped tbsp pumpkin seeds, dry toasted or roasted
- lime quarters, to serve
For the dressing
- 4 tbsp light soy sauce
- 5 tbsp olive or rapeseed oil
- 1 tbsp Thai fish sauce
- juice and zest of 1 lime
- 1 level tbsp finely chopped
- fresh ginger
- 1 red finger chilli, deseeded and finely chopped
- 1 garlic clove, finely chopped
- 1 tbsp runny honey or maple syrup
- 30g fresh coriander leaves and stems, roughly chopped
Peel and cut the sweet potato into 1cm slices and steam for 5-7 minutes, or until just soft to the tip of a knife. Cool.
Whisk all the dressing ingredients together and put to one side for the flavours to infuse. Season with freshly ground black pepper to taste.
Heat a ridged griddle pan or heavy-based frying pan for 3-4 minutes (until you can’t count to ten with your hand hovering just above it). Brush on rapeseed or coconut oil and griddle the sweet potato slices in batches for about 3 minutes per side. Keep each batch warm in a low-heat oven while you cook the rest.
In a large bowl, pour most of the dressing over the salad leaves and toss well to coat.
Serve on individual plates, adding a good handful of salad leaves to each one and topping with three or four griddled sweet potato slices. Finish with an extra drizzle of dressing, roughly chopped coriander and toasted pumpkin seeds. Serve with lime quarters.
ADZUKI BEAN AND ROOT VEGETABLE CHILLI
Preparation 25 minutes, plus soaking. Cooking 1 hour 40 minutes.
Make this fantastic meal in a pot in a big batch and eat over several days. Even devoted carnivores will like this chilli and, served with red or black rice, it has all the flavours of a Moroccan lamb tagine. As well as the sweet potatoes and other root vegetables, the adzuki beans contain compounds that help to lower cholesterol and decrease blood pressure.
- 200g dried adzuki beans
- 2 tbsp olive oil
- 1 large onion, finely chopped
- 2 sticks of celery, finely chopped
- 1 red pepper, deseeded and finely chopped
- 1 red chilli, deseeded and finely chopped
- 2 garlic cloves, crushed
- 150g each of sweet potato, celeriac, carrots, swede and parsnips, peeled and cut into large chunks
- 2 bay leaves
- ½ tbsp cumin seeds, toasted and ground
- ½ tbsp dried oregano
- ½ tbsp paprika
- 1 tsp chilli powder
- 1½ tsp ground cinnamon
- 400g tin chopped tomatoes
- 200g passata
- 2 tbsp golden sultanas
- 500ml hot vegetable stock
- 30g fresh coriander leaves, roughly chopped
Put the dried adzuki beans into a large bowl, cover with cold water and leave to soak overnight.
Heat the olive oil in a casserole dish over a medium hob, add the chopped onions, celery, pepper, chilli and garlic, and cook for about 10 minutes until softened.
Add all the root vegetables to the casserole, along with the bay leaves, cumin seeds, oregano, paprika, chilli powder and cinnamon. Stir well, then add the drained adzuki beans, the chopped tomatoes, passata and sultanas. Season with flaky salt and freshly ground black pepper.
Cover and simmer for 30 minutes, stirring at regular intervals to prevent sticking, or cover and cook in the oven at 160°C (140°C fan oven) / gas mark 3 for 1 hour. Add the stock and return to the oven for 30 minutes. Check the seasoning and serve garnished with the fresh coriander.