- Mince green onion, separating white part from top.
- Heat oil in medium saucepan over high heat, stir in white part of green onion. Add tomato, mushrooms, chicken broth, water, soy sauce and dry sherry. Bring to a boil; reduce heat, cover and simmer 5 minutes.
- Blend cornstarch with 3 Tbsp. water; stir into saucepan. Add green peas; cook over high heat, stirring constantly, until mixture boils and is slightly thickened.
- Gradually pour egg into boiling soup, stirring constantly, but gently, in one direction.
- Remove from heat, stir in green onion top and white pepper.