Add 1 tea spoon of : sesame oil, oyster sauce, oil, ‘hua diao’ Chinese wine.Pour all of them on the fish in the alminium foil tray, then add in the gingers and mushroom.
Seal with aluminum foil and put in my ‘snack oven’. 
My old oven only having 15mins maximum setting, I need t cooks twice, means 15mins + 15mins to make sure the fillet thoroughly cook.
It doesn'tlooksnice, but I like the taste. :)