Heat the oil in a saucepan. Add the ground coriander, saffron, ginger and onion. Fry for 1-2 minutes until golden yellow.
Add the carrots and the stock. Bring to a boil, then add the sweet potatoes.
Simmer the soup for 10 minutes, then add half the chickpeas. Remove from the stove, and using a hand mixer blend till silky and creamy.
Add the other half of the chickpeas ( perhaps chopped), bring it to the boil. Then mix in the lemon juice and the chopped herbs. Season to taste.
Serve warm with rusty bread or pita.