Wash the napa leaves and dry in a strainer.
Chop the onion finely and microwave 2 mins. Set aside and allow them to cool.
Place all of the filling ingredients including step 2 onion in a mixing bowl. Combine well until it gets sticky.
Place napa leaves on a big flat pan and spread the filling(1/9 each).
Put one more leave each, and spread the filling again. Repeat this again and cover with napa leaves.
Add 1 cup of water and cook over medium heart with a lid. Bring it a boil, reduce the heat and simmer about 12 mins or until the chicken is completely cooked.
While you are cooking them, combine the sauce ingredients except potato starch and water.
When the chicken is done, place them on plates upside-down and cut if needed.
Add the mixture from step 7 into the pan and bring it a boil with water from napa and chiken.
Add potato starch to make the sauce thicken. First mix potato starch and water well, then add it into the boiling sauce in your pan. Mix immediately to keep lumps and cook until the sauce thicker.
Pour the sauce on the Mille Feuille and enjoy!
