Finely chop the onion and garlic. Peel and dice the sweet potatoes and carrot.
Heat a spoonful of oil in a large saucepan and gently sauté the onion and garlic for about 5 minutes, until soft.
Add the sweet potatoes and carrots, put a lid on and steam for 5 minutes. Add the spices and paste, stir for a minute then pour in the stock. Bring to the boil, then gently simmer for 10 minutes under cover.
Add the broccoli florets and cook for a further 8-10 minutes until tender.
Turn off the heat. Add the fresh coriander and, using a hand blender, process the soup until you get a smooth or textured consistency, depending on your liking.
Serve warm, drizzled with lime juice.