Red Thai Chicken Curry Soup

They made this soup at the co-op and I sampled some and thought it was very yummy, so I wrote down the ingredients that they had listed (although they did not include the amounts), and came up with this (which is pretty darn amazing!):

1 yam (or sweet potato, whatever)
1 onion, diced
Chicken, cut up (from when I do this)
1 T cilantro
2 tsp salt
1/2 tsp pepper
4 c. chicken broth
1 can coconut milk
1 T red curry paste
1 T cornstarch

Heat everything through, simmer for a little bit, and serve!