1. Beat egg whites lightly.
2. Dissolve corn flour in one fourth cup vegetable stock or water.
3. Wash and chop tomatoes finely.
4. Peel and chop onion and garlic.
5. Peel, wash and chop ginger finely.
6. Clean, wash and chop fresh coriander leaves.
7. Heat oil, add chopped ginger and garlic and stir fry for a half a minute.
8. Add chopped onion and continue to stir fry till onions are soft and translucent.
9. Add tomato ketchup and chopped tomatoes.
10. Cook for about five minutes.
11. Add stock or water add salt and white pepper powder to taste and stir. Bring to a boil.
12. Add corn flour dissolved in vegetable stock or water, a little at a time stirring continouously till soup turns to a thick soup consistency.
13. Add white vinegar and stir.
14. Pour beaten egg white in a steady thin stream, while stirring lightly, allow it to coagulate.
15. Stir in chopped green coriander, reserve some for garnishing.
16. Serve hot immediately, garnished with chopped green coriander.