This is a great tasting soup. It's a Jill Dupleix recipe that I modified. Her recipe is here. I didn't have curry powder, so I substituted ground cumin and coriander instead. I also added bay leaves and a parmesan rind to the stock while the sweet potatoes were cooking, just to up the flavour ante. I topped it with a swirl of sour cream, paprika and olive oil, and scattered over some fresh coriander. This soup is nice at lunchtime when served with some crusty bread.