The sweetness of sweet potatoes is perfectly balanced with the spiciness from the red chilies and the tanginess from lime. The fish sauce (soy sauce for vegan) rounds it all up. This soup is a harmony between flavors which are sure to awaken your taste buds.
Thai cuisine is all about balancing flavors: sweet, sour, salty and spicy. This soup is a perfect depiction of those flavors. We start by dry roasting some spices and aromatics which brings a nice smokiness to them. They are then grinded into a mortar and pestle to release their aroma. You will already know at this point that the soup is going to be loaded with flavors. Some kaffir lime leaves are added to give that distinct lemony aroma, followed by some lime juice, fish sauce and coconut milk.
Ingredients at a glance:
Thai Sweet Potato Soup
- 3 big sweet potatoes
- 1/2 red onion
- 3 cloves garlic
- 1 piece ginger (4 cm)
- 1 stalk lemongrass
- 5 black peppercorns
- 2 cloves
- 2 green cardamom pods
- 1/2 tsp coriander seeds
- 4-5 kaffir lime leaves
- 4 thai red chili (bird's eye chili)
- 200 ml (1 cup) coconut milk (full fat)
- 1 Tbsp fish sauce (substitute soy sauce for vegan version)
- juice of 1/2 lime
- Peel and roughly dice the sweet potatoes. Peel and chop the onion, garlic and ginger. Thinly slice the white part of the lemongrass.
- Put a pan on medium low heat and dry roast the black peppercorns, cloves, cardamom and coriander seeds. Continue stirring and roast for 5 minutes. Remove from the pan and set aside.
- Add the chopped onion, garlic, ginger and lemongrass to the pan and dry roast them for 7 minutes. Keep stirring for even roasting. After 7 minutes, remove from pan and set aside.
- Transfer the dry ingredients first to a mortar and pestle (or a grinder) and roughly crush them (no need for a fine powder). Gradually add the dry roasted onion, garlic, ginger and lemongrass, and crush them as well to make a coarse mixture.
- Now, put a big pot on medium heat and melt the coconut oil.
- Add the spice mixture and saute for 1 minute.
- Add the sweet potatoes and coat well with the spices.
- Add salt, kaffir lime leaves, chopped thai red chilies and water.
- Cover and cook on medium heat for 15 minutes.
- Turn into a smooth paste either using a stab mixer or a blender.
- Add coconut milk, fish sauce and lime juice. Mix well and taste to adjust seasoning.
- Serve with lime wedges, sliced spring onion and some extra chopped chili (if preferred spicy).