Thai-Style Sweet Potato Soup


Preparation info

  • Serves


    • Difficulty


Appears in

The Mountain Cafe Cookbook

The Mountain Cafe Cookbook

By Kirsten Gilmour

Published 2017

  • About

A smooth sweet potato soup with a refreshing Thai twist.

  • To make this vegan, just leave out the fish sauce.
  • When preparing lemongrass, you want to keep the lemongrass as a single piece as you’re going to remove it from the pan before blitzing. Cut it in half lengthways but stop before you get to the bottom, leaving the bulb intact. Then use a small pan or a kitchen mallet to bruise it – this helps let all the flavour out.


  • 2 tablespoons olive oil
  • 1 medium onion, roughly chopped
  • 2 garlic cloves, chopped
  • 15 g fresh ginger, peeled and chopped
  • 1 lemongrass stalk, almost halved lengthways
  • 3 lime leaves
  • 1 handful fresh coriander, stalks and all, roughly chopped (plus more for garnish)
  • 2 to 3 tablespoons red Thai curry paste (depending on how spicy you like it)
  • 400 g sweet potatoes, peeled and cut into equal small chunks
  • 1 x 400 g tin of coconut milk
  • 900 ml vegetable stock (or 2 stock cubes dissolved in 900ml hot water)
  • 1 tablespoon dark brown sugar
  • 3 tablespoons fish sauce
  • 1 lime, zested and halved
  • 1 tablespoon desiccated coconut (to garnish)
  • freshly ground black pepper


    Heat the olive oil in a heavy-bottomed soup pan over a medium-high heat. Add the onion, garlic, ginger, lemongrass, lime leaves and fresh coriander and sauté until the onions start to soften. Stir in the curry paste, then tip in the sweet potatoes and mix. Pour the coconut milk and stock into the pan and add the brown sugar, fish sauce and the lime zest. Squeeze the lime halves into the soup and then throw in the squeezed halves for good measure.

    Bring to the boil and keep at a steady simmer until the sweet potatoes are cooked – roughly 30 to 40 minutes. Use tongs to carefully remove the lemongrass and lime halves and discard them, then blitz the soup until smooth. Add a bit of hot water if it’s too thick, then taste and season with more fish sauce and some black pepper if it needs it. Serve with chopped fresh coriander on top and a sprinkle of coconut – I am also a sucker for adding some chopped roasted peanuts and a squeeze of lime juice.