Break the white fungus into bite-sized pieces, making sure to remove and discard the hard brown stem portion. Place in a bowl and cover with cold water, and let soak for 20-30 minutes. Drain off the water.
Place the lotus seeds in a small bowl and cover with hot water. Let soak for 5-10 minutes, then drain off the water. Gently break them in half with your fingernail along the seam, and remove any little sprout that’s inside.
Bring the water to a boil in a medium pot, then take off the heat and add the black tea. Let steep for 3-5 minutes, then discard the tea leaves.
Place the pot of tea back on the stove, then add the white fungus, lotus seeds, dates and ginger.
Cook for 15 minutes (it's okay if it's not boiling the whole time), or until the lotus seeds are soft. Mix in the brown sugar and salt.
Then, stirring continuously, pour in the egg. The quicker you stir, the smaller the egg wisps in the soup will end up. I personally like them on the larger side, so I stir a little more slowly.
Ladle into bowls and serve hot!
Recipe Notes
This soup can be made ahead of time and stored in the fridge for up to a week, or in the freezer for a few months.