Remove the stems from the shiitake mushrooms and slice the caps.
Quickly fry the mushrooms in a non-stick pan over a high heat in the hot oil, turning them brown.
Put the contents of the pot of Tjap Tjoi in a saucepan and add the stock.
Bring the soup slowly to a boil.
Add the strips of chicken breast, the fried mushrooms and the corn and simmer for about 3 minutes.
Just before serving, stir the Spinach and the cream into the soup and let it boil for another 1 minute. The spinach is soft but still has bite and color.