Inspired by a soup that we had at Hai Chinese Restaurant last night, this soup dish is a kaleidoscope of subtle flavors. The base is fish broth but neither the fishy aroma nor flavor is overpowering. What stands out, but oh, so subtly, is the slight crunch of the onion leaves and the whiff of what the menu said was Chinese celery but which Speedy doubted because Chinese celery (kinchay) is stronger both in flavor and smell. I deconstructed the dish and made my version for lunch today, using coriander leaves (cilantro) instead of Chinese celery. As we savored the soup, we both knew that Speedy was correct the first time. Coriander leaves indeed; not Chinese celery.
To achieve that wonderful balance of subtle flavors, the key is to use spices sparingly. The broth was made with the usual combination of onion, garlic, and ginger but in smaller amounts than usual. Once you have the correct broth and this is essential the rest is nothing more than assembly.
Make the broth. Place the fish, ginger, onion, and garlic in a pot. Cover with water, season with salt and pepper, bring to a boil, lower the heat, cover, and simmer for about 20 minutes. Strain the broth into a clean pot. Reserve a small about for the starch solution. Separate the fish flesh from the bones; discard the bones. Leave the fish flesh in fairly large pieces if they are any smaller, they are likely to fall apart and become invisible in the soup later.
Reheat the broth. Add the onion leaves, carrot slices, and mushrooms. Boil for about a minute. Disperse the starch in the reserved broth. Pour into the soup. Stir. You’re only thickening the broth slightly so don’t expect the consistency of a sauce. Cook for about 30 seconds then turn off the heat. Add the fish flesh. Stir. Pour in the beaten egg in a thin stream, allow to set for a couple of seconds then stir lightly. Add the coriander leaves, give the soup, and final stir, and serve.