Heat up a large pot on medium heat, and add neutral oil. Once hot, add the scallion whites and stir fry for 1 minute.
1 tbsp neutral oil, 2 stalks scallions
Add the chicken broth and mushroom water to the pot. Turn up the heat to high to bring it up to a boil.
8 cups low sodium chicken broth
Add all the seasonings except for the vinegar and sesame oil. Give the soup a mix.
1/4 tsp salt, 1/4 tsp white pepper, 1/4 tsp sugar, chicken bouillon, 1 tbsp light soy sauce, 1/2 tsp dark soy sauce
Add frozen dumplings (if using). Let the soup simmer until the dumplings float to the top.
frozen dumplings
Add the rest of the sliced veggies and tofu. Mix and let simmer for 2 minutes.
Make sure the soup is still simmering. Dissolve any settled cornstarch in the cornstarch slurry, then add it to the soup while stirring. It should thicken almost immediately. Feel free to add more if you prefer the soup thicker.
Turn off the heat, then slowly drizzle in the beaten egg while stirring slowly to create beautiful ribbons.
Finally, add the vinegar and sesame oil. We save the vinegar for last because vinegar loses its sourness as it boils.
2.5 tbsp Chinese black vinegar, 1/2 tsp sesame oil
Adjust any final seasoning if necessary. I like to add more white pepper here. Garnish with scallion greens. Enjoy!