Heat the oil in a pot over medium-high heat. Add ginger and stir frequently for 1-2 minutes. Add water and chicken bouillon, then bring the mixture to a boil.
Add in fish sauce and light soy sauce to the pot.
In a small bowl, whisk the eggs using a fork. Drizzle the eggs gently into the boiling broth mixture.
Add in white asparagus and crab meat, and stir.
Add the cornstarch mixture and continue stirring until the soup is slightly thickened, about 1 minute or so.