I finally start to make my own favourite dessert, 'cheng teng'. I put in gingko, longan, white lotus, winter melon, etc. It tasted very good, not those taste sold by the hawkers. It's naturally sweet, but the ingredients in the soup lost all their taste.
I learnt something from this experience, I have to prepare another set of fresh ingredients to be added in separately when serve.
A good 'cheng teng' cost around $2.50 for a small bowl of it. Now I can use the same amount to cook a pot of it.