Sweet Potato Soup

Ingredients:

300g orange-fleshed sweet potatoes
300g Japanese sweet potatoes
50g dried longans
2500 ml water
120g rock sugar
3 pandan leaves, knotted
1 thumb-sized piece ginger

Method:

1.  Peel and cut sweet potatoes into chunks.  Wash and flatten ginger with the back of a cleaver.
2.  Place 2.5 litres of water in a pot together with the ginger and pandan leaves.  Bring to a boil.
3.  Add in the dried longans, sweet potatoes and rock sugar.  Simmer for 15 to 20 minutes or until the sweet potatoes are just tender.
4.  Discard pandan leaves and serve.