Cut and prepare the ingredients.
In a steamer over medium heat, add enough water to boil for about 30 minutes. Cover and let it boil for 15 minutes.
Marinate the inside and outside of the fish with 1/2 tbsp of salt, rubbing evenly to distribute it.
Add 20g of ginger to the steaming plate, and place the fish, inside facing down, onto the plate. Sprinkle another 15g of ginger strips all over the fish.
When the water is boiling vigorously, place the steaming plate into the steamer and cover the lid. Let it steam on medium for about 10 minutes.
In a separate pan over medium heat, add the cooking oil and wait 30 seconds for it to heat up.
Add 75g of ginger strips to the pan, stir-frying continuously for 4 to 5 minutes, or until crispy and golden brown. With a strainer, remove the ginger strips, shaking off the excess oil and set aside.
Add the minced garlic to the hot oil, stir-frying for about 2 minutes, or until crispy and golden brown. Switch off the heat. Remove with a strainer, shaking off the excess oil. Place them on another plate and set aside.
Remove the excess oil, leaving about 2 tbsp in the pan. This oil can be stored once cooled, to be used in other stir-fry dishes, or as a condiment over noodle soups.
Switch on the heat to medium. Add 200ml of water, light soy sauce, sugar and black sesame oil to the pan. Stir until the sauce is well-combined. Let it come to a rolling boil. This takes about 1.5 minutes. Switch off the heat, and pour the sauce into a heat-resistant cup and set it aside.
After the fish has been steaming for 10 minutes, carefully remove it from the steamer with a clamp, and drain the fishy water into a separate bowl. Place the steaming plate back into the steamer. Pour all the soy sauce mixture onto the fish. Cover the lid and let it steam for another 5 minutes.
After 5 minutes, switch off the heat. Carefully remove the steaming plate with a clamp, and place it on a heat-resistant coaster.
Garnish with fried ginger strips, crispy fried garlic and chopped spring onions. Serve immediately.