1. In a small bowl, mix together water and rice flour, to make thickener.
2. Using paring knife, scrape the white fibre off the tangerine peel.
3. In a tall saucepan, put the red beans with 400 ml of water.
4. Cover the saucepan and bring the water to boil.
5. As water starts to boil, reduce the heat to medium and allow to cook for 20 minutes.
6. Turn off the heat, and leave the pan on the stove for 10 minutes.
7. Drain the water.
8. In a large pot, put the red beans, tangerine peel and 700 ml water.
9. Cover the saucepan and bring the water to boil.
10. As water starts to boil, reduce the heat to medium and allow to cook for 20 minutes.
11. Turn off the heat, and leave the pan on the stove for 2 hours.
12. Add 800 ml of water to the pot.
13. Cover the pot and raise the heat to high and bring to boil.
14. Reduce the heat and simmer the beans for about 2 hours or until beans are soft and split easily.
15. Turn off the heat and leave the pot on the stove for 1 hour.
16. Remove the tangerine peel and set aside.
17. In a electric blender, blend the bean mixture in batches.
18. In a pot, put the bean puree, brown sugar, salt and tangerine peel.
19. Allow to boil on high heat until the sugar is dissolved.
20. After the sugar dissolves, remove foam from the surface if there is any.
21. Reduce the heat and add thickener little at a time, stirring continuously.
22. As the puree starts to boil, turn the heat off.
23. Cover the pot and leave it on the stove for 30 minutes.
24. Stir and serve Yum cha red bean soup. If serving this soup cold, drizzle little cream on top.