Discard any wilted leaves of choy sum; Trim an inch from the tough stems; Rinse them under running water; Soak them in water for an hour; Remove them; Rinse them under running water again; Drain them.
Rinse and drain an egg; Set an egg separator over a basic glass bowl; Break the egg into the egg separator, draining the egg white into the bowl.
Add seasoning and the egg white to a mixing bowl; Mix.
Scrape the scales of grouper fillets with a fish scaler; Rinse them; Pat-dry them with kitchen paper; Slice them; Marinate them with the seasoning mixture from the step 3 for 30 minutes.
Fill a deep plate with water; Stir 2 tsp salt into water; Carefully arrange firm tofu into the salty water; Leave it for 30 minutes; Discard the salty water; Slice it.
Rinse and drain coriander; Slice off any roots and stems; Chop it.
Rinse and drain spring onion; Cut off any roots; Chop it.
Rinse and drain red chili peppers; Slice off any stems; Bisect each lengthwise with a vegetable knife; Scrape any seeds out; Chop them.
Fill a saucepan with water; Bring to the boil over a high heat; Add 1 tbsp oil and the choy sum; Blanch them for 1 minute; Immediately remove and drain them; Turn off the heat.
Fill a wok with water; Stack a bamboo steamer in the wok; Bring to the boil over a high heat.
Arrange the coriander and most of the spring onion on steaming plates; Place the tofu on the top of the coriander and spring onion; Arrange the grouper fillets on the top of each piece of tofu; Sprinkle the red chili peppers and fermented black beans on the grouper fillets; Surround the tofu pieces with the grouper fillets with choy sum; Arrange the steaming plates in the bamboo steamer; Steam over a high heat for 7 minutes; Turn off the heat; Ready to serve.
Add 4 tbsp oil to a slant-sided saucepan; Bring to the boil over a high heat; Turn off the heat; Immediately drizzle the boiling oil over the grouper fillets; Garnish them with the remaining spring onion; Ready to serve.