Fan Kok Soup (Arrowroot Soup)

I dunno what is the scientific English name for Fan Kok.I guess you can called small yam or taro.It's has the same texture and color as the regular taro.Anyway,I know lots of chinese like to use fan kok to make soup. I bought some fan kok on sale month ago,I guess the only way I know how to cook fan kok is to make soup.This fan kok soup is delicious and healthy.

Ingredients:

5-6 pieces fan kok,peeled ,washed and cut 1/2
5 liter water
2 small carrot,peeled,washed and cut 2 inch
1 large piece pork in bone,cut into4 pieces
salt to taste
some cut scallion Method:

1:Prepare a large stock pot with 1 liter water at high heat.When water rolling boil add in pork in bone .Cook for 5 minutes until the oil surface,remove pot from heat .Wash pork in bone with cold water,set aside.
2:Use the same pot ,fill with 4 liters water , pork in bone,carrot and small yam.Cook at medium heat for 1 hour or more.Add in salt to taste.
3:Dish our and serve warm.