With the big freeze hitting London, all I want to eat it food that warms you through. This soup is definitely warming, filling and of course – tasty.

The slight ‘exotic’ combination of sweet potato and lemongrass really works and it is a nice alternative for a mid-week meal.

The vegetable puré itself is velvety and thick enough without the addition of dairy product, however I think a dollop of creme fraiche while serving adds another flavour, and it cuts through the lemongrass nicely.

(To make this vegan, use vegetable stock and omit the creme fraiche.)

Sweet potato and lemongrass soup, serves 2

2 sweet potatoes

1 lemongrass

1 tbsp olive oil

400 ml chicken or vegetable stock

salt, black pepper

To serve: a dollop of creme fraiche and a drizzle of olive oil

Peel the sweet potatoes and cut into even-sized pieces. Cut the lemongrass in half lengthways and then across so you have four pieces. Heat up the oil in a large saucepan on medium heat. Add the lemongrass and sweet potato and stir for a few minutes to enhance the flavours. Add the stock and bring to the boil. Then cook with the lid halfway on for about 15 minuter or until the vegetables are soft. Remove the two thickest pieces of lemongrass then puré the everything into a thick soup consistency. Add more stock or hot water until it has the thickness you want. Bring to the boil again and season. Serve with a dollop of creme fraiche and a drizzle of a flavoursome oil.