Combine all elements for the sauce into a small bowl.
Thinly slice the ginger into a fine julienne. Slice the scallions at a diagonal angle.
Cut to the fish into thick chunks and place on absorbent paper to absorb excess moisture. Coat lightly on all sides with cornstarch.
Add the oil to a non-stick pan over medium heat and when hot, fry the ginger until lightly golden and crispy.
When the ginger is fried, take out of the oil and reserve.
To the remaining oil, add the coated fish. Pan-fry the fish pieces for a couple of minutes on each side. When cooked, carefully remove the fish from the pan.
Add the scallions to the pan and allow to wilt slightly.
Add the sauce ingredients and half of the fried ginger and allow the sauce to thicken and become transparent and glossy.
Last add in the fish and turn gently to coat with the sauce, being careful not to break the fish. Remove from the heat to prevent the fish from overcooking.
Serve with fluffy rice or noodles.
Notes
The cooking time of the fish will depend on the fish you are using. If using a firm fish or thicker pieces, the cook time will be longer. Test a piece for 'done-ness' when the fish looks cooked.