Soak woodear mushroom in a bowl
Fill half of pot with water and place on medium-high heat, place lid on to maintain heat/speed it up
Slice tofu into slender column stacks, then gently transfer to pot
Add soy sauce, rice vinegar, woodear, and white pepper. Gently stir.
Bring all to a boil and let simmer for 15-20 min to let flavors meld together
Add corn starch (make sure to add water to corn starch in a separate container and to mix with water before adding to the soup --- do not directly add to soup),
Stir and bring to a boil
Once soup is boiling, drop in and beat in egg, making sure to beat the egg immediately to create the ribbon effect. (Important: Soup must come to a boil first!)
Stir and let simmer on medium-heat for 15 min.
Serve and add green onions to garnish