Sautee the tomatoes: Heat oil in pot, add tomatoes in. Fry for 1 minute until the tomatoes becomes quite soft.
Add water: add water or stock in.
Season and adjust texture: season with salt and white pepper as well as soy sauce . Let the soup base simmer for around 10 minutes. Then pour in the starch water mixture.
Swirl in the eggs : crack the eggs into a small bowl and beat lightly with a fork. While stirring the simmering soup, slowly drizzle in the eggs so they form thin ribbons.
Finish and serve: turn off heat as long as the ribbones formed. Add chopped scallions and any other toppings.