Heat the vegetable oil in a pot over medium heat. Once hot, add the tomato chunks and cook, stirring occasionally, until the tomatoes start to break up. Roughly 3-4 minutes.
2 Tbsp Vegetable Oil, 3/4 Lb Tomatoes, Roughly Chopped
Add the chicken stock, soy sauce, 1/4 tsp of pepper and a heavy pinch of salt to the pot. Raise the heat to high and bring the soup to a boil, stirring occasionally.
3 C Chicken Stock or Broth, 2 tsp Soy Sauce, 1/4 tsp White Pepper, Salt and Additional Pepper to Taste
Once the soup reached a boil, reduce the heat to a simmer.
In a separate bowl, whisk the corn starch and water together with a fork, until the corn starch is fully mixed with the water.
3 Tbsp Water, 1 1/2 tsp Corn Starch
Stirring the soup slowly, stream this cornstarch mixture into the soup. Stir until fully combined. The soup with start to thicken pretty quickly.
In a separate bowl, beat the egg with a fork until the yolk and whites are fully combined.
1 Egg
Stirring slowly and continuously, pour a steady stream of this beaten egg into the soup. The constant stirring is what helps form the egg into ribbons in the soup (rather than basically a big clump), so don't stop stirring during this step. Once all the egg is added, add the sesame oil and taste for salt and pepper.
1/2 tsp Sesame Oil
Serve hot, garnished with your sliced green onion.
1 Green Onion