Heat up water or stock to be 40-50℃. Or you can boil it and then leave it to cool. If the liquid feels warm on the hand but not hot, that's the best for egg custard
Beat the eggs into a measuring cup, mine came up to be 100ml
Pour in about 125 ml of water (can use a measuring cup)
Stir to mix the water/stock and egg and add salt if needed. If adding a sauce, you might not need salt.
Use a small strainer and strain out the egg mixture into a bowl. You might have some leftovers in the strainer, just leave it out.
use a cling film/saran wrap and wrap the bowl. Poke some holes on to the top
Fill a steamer with water and steam on high for 10-12 minutes (optional: boil the water beforehand and decrease cooking time.) If you like it slightly less firm, do about 7 minutes.
Make the scallion soy sauce mixture when waiting for the egg custard.