Chop and mince the Japanese pickled ginger. Heat up oil, then, pour the oil into the ginger mix.
Mix the ginger with chicken powder. Add a pinch of salt and add sugar, mix and set aside.
Place some potato starch (or cornflour) in a bowl, gently dip the fillet into the bowl then lightly pat off the starch coating.
Place the fillet onto a dish, put the mixed ginger on top of the fillet and steam for 15 minutes. (Steam for a longer period if the fillet is thicker).
While the fish is steaming, prepare the sauce. Put water into the saucepan and add in fish sauce, light soya sauce, chicken powder, sugar and dark soya sauce over medium heat until the sauce boils up. Remove the sauce from heat.
Remove the fish from the steamer and pour the sauce onto the fish. Decorate with shredded shallots and other edible greens and serve.