Whisk the eggs with the salt until the yolks and whites are fully combined, but stop before it gets foamy. Stir in the warm water, then pour through a fine sieve into a shallow heatproof bowl, about 20 cm / 8 inches wide. Pop any bubbles on the surface with a toothpick.
Cover the bowl tightly with a plate or foil so condensation cannot drip onto the custard. Set up a steamer with simmering water and place the bowl inside.
Steam over medium-low heat for 10 minutes, keeping the lid slightly ajar with a chopstick if the water is boiling hard. The custard should be mostly set with a slight wobble in the center.
While it steams, heat the oil in a pan over medium-high heat. Add the pork and break it up, cooking 3 to 4 minutes until no pink remains and the edges brown. Add the garlic for 20 seconds, then the Shaoxing wine, 1 tbsp light soy sauce, sugar and white pepper. Cook 1 minute until glossy. Turn off the heat.
Uncover the custard and gently place the tofu cubes on top. Cover again and steam 3 more minutes, until the center barely jiggles and a toothpick comes out clean.
Spoon the pork over the top. Drizzle with the remaining 2 tsp soy sauce and the sesame oil, scatter over the scallions and serve right away, spooned over rice if you like.