On medium high heat, in a pot, add some oil and add in the scallion to stir fry for 1-2 minutes
Add in the tomatoes and add salt. Stir fry until the juices started to come out of the tomatoes (3-4 minutes)
Add in water.
Then add in tofu, enoki, wood ear mushroom.
Add in black Chinese vinegar, soy sauce and white pepper.
Let it come to a boil (4 minutes)
Once it's boiling, let it boil for about 1-2 minutes then add in beaten egg.
Once the egg is cooked then it ready.
Optional: if you want the soup to be thicken, then mix about 1 tsp of corn starch with 2 tbsp of water. Add to the soup to thicken.
Add a bit of chopped scallions to garnish and serve.