When you are out in the cold for a couple of hours, a few things are as nice to come back home to as a warming soup or stew. This Thai red lentil soup with sweet potatoes has been my go to lately and it never fails to deliver. It came about from me wanting to use up a pot of red Thai curry paste I had. I also wanted something quick and simple that doesn’t require a lot of work and this Thai red lentil soup is it.
It is a riff on this simple peanut and sweet potato curry I made ages ago but I simplified it further by getting rid of all the aromatics. Forgoing the aromatics may sound bold but if you have a good quality curry paste, it will do all the heavy lifting for you. Other than frying the paste off, this soup needs you to simmer some quick cooking red lentils and cubes of sweet potato for about fifteen minutes and you are done. Like with most soups and stews, I recommend making it at least a day in advance, but if that’s not an option, don’t worry – it will still be delicious and nourishing.
Oh and if you fancy a lentil soup, but not in the mood for Thai-inspired one, you may want to give this one a go instead. Enjoy!
MORE ABOUT THE INGREDIENTS
THAI RED CURRY PASTE: Red Thai curry paste contributes most flavour to this dish so it’s important to use a quality paste. I used Mae Ploy paste, which comes in both veggie and regular variety.
RED LENTILS: Split red lentils are commonly available in the UK, they are cheap and cook quickly – perfect for stews and soups.
SWEET POTATO: Sweet potato contributes extra nutrition, plus another flavour and texture to this Thai red lentil soup. You can use any colour of sweet potato really, but I chose orange as it makes the soup look appealing. Plus, it’s the most commonly available variety in the UK.
SUGAR: A touch of sugar is needed here to fine tune the flavour of this soup. It doesn’t matter what sugar you use, it’s only used for a touch of sweetness.
VEGAN FISH SAUCE: Vegan fish sauce is typically made with kombu and shiitake as these two ingredients infuse it with a bit of funk and extra depth of flavour. I got mine in the Asian supermarket.
LIME: A touch of lime juice is here to balance the sweetness of this soup. Add lime juice at the end as simmering will dull its flavour and adjust the amount to your taste.
TOMATO POLPA: I added a can of tomatoes to bulk up this soup and to add a little bit of freshness. I opted to use finely minced tomatoes (polpa) for speed, but you can use whole peeled or chopped tomatoes too. I do recommend you squash them down with potato masher first to speed up the cooking time though.
COCONUT MILK: Full fat coconut milk adds lovely creaminess to this simple soup.
PEANUT BUTTER: As well as coconut milk, I added a bit of peanut butter for extra flavour and texture. If you cannot have peanut butter, almond butter will work too.
CORIANDER / CILANTRO: Finally, a generous handful of fresh coriander is what I garnished the soup with at the end. I am a massive coriander fan, but if you aren’t, you can skip it. Or maybe zest a couple of limes on top to compensate for the citrusy notes that coriander contributes to this dish.
HOW TO MAKE IT?
1) FRY OFF THE PASTE
Fry the curry paste off in a bit of oil in a heavy bottom pot. Make sure to keep the heat low-medium and to stir the paste frequently. Once the red oil starts separating from the solids, carry on frying the paste off for another 5 minutes. Make sure it does not burn though – keep the heat low, stir often and add a splash of coconut milk if it’s looking too dry at any point.
2) SIMMER TOMATOES
Next add tomatoes and a bit of water and simmer until the tomatoes are cooked. If your tomatoes are whole or in big chunks, rather than finely minced like mine, squash them down with a potato masher first to ensure they cook a little quicker.
3) COOK LENTILS & SWEET POTATO
Once the tomatoes are no longer raw, add thoroughly rinsed red lentils and cubes of sweet potato and a generous amount of water. Simmer until both lentils and sweet potato cubes are cooked through.
4) ADD CREAMINESS & SEASON
Finally, add in two creamy ingredients – coconut milk and peanut butter. Season with sugar, vegan fish sauce and lime juice to your taste. Allow the soup to cool down completely then store in the fridge overnight if not serving immediately.
- 60 ml / 4 tbsp neutral oil, like grapeseed or peanut
- approx. 80 g / 4 tbsp quality red Thai curry paste*
- 1 x 400 g / 14 oz tin of minced tomato (POLPA)*
- 300 g / 2 cups split red lentils
- 1 kg / 35 oz (2 large) orange sweet potatoes
- 1 x 400 g / 14 oz full fat coconut milk
- 60 g / 4 tbsp peanut butter
- approx. 1 tbsp sugar, adjust to taste
- approx. 2 tbsp vegan fish sauce, adjust to taste
- approx. 2-3 tbsp lime juice, adjust to taste
- chopped fresh coriander/cilantro, to serve
- Heat the oil up in a large, heavy bottom pot.
- Add red Thai curry paste to the hot oil. Fry the paste off stirring the whole time and keeping the heat low-medium. Once red oil starts to separate from the solids, continue frying the paste off for another 5 minutes. If the paste is looking too dry at any point, add a splash of coconut milk.
- Next add in the tomatoes, a good pinch of salt and a cup of water. Bring the tomatoes to a gentle simmer and allow them to simmer away for about 15 minutes, until thickened.
- While the tomatoes are simmering away, cube your sweet potatoes into same size, medium (approx. 1 cm / 0.4 inch) cubes.
- Add a generous pinch of salt, well rinsed red lentils, cubed sweet potatoes and 1.5 l / 6 cups of water to the pot. Cover the pot with a lid.
- Bring everything to a simmer and simmer gently for about 15-20 minutes, until the lentils are cooked and potatoes are cooked through.
- In a small bowl, peanut butter with a bit of coconut milk to loosen.
- Once both lentils and sweet potatoes are fully cooked, add coconut milk and peanut butter. Stir well. If you want the soup a little thinner, add a splash more water.
- Taste and season with vegan fish sauce, sugar and lime juice.
- Cool down and overnight in the fridge for the best taste or, if serving immediately, divide between bowls and season with fresh coriander.
*RED THAI CURRY PASTE: the amount depends on the paste (the brand I used is Mae Ploy) and your heat tolerance. This recipe makes a lot of soup so I landed on 4 tbsp, which gives subtle background kick. If you want more heat, you can always add more in your next iteration.
*TOMATO POLPA: instead of polpa (finely minced tomatoes), you can also use whole peeled tomatoes or tomato chunks. To speed the cooking process up, use a potato masher to pulverise your tomatoes first.