Cut off ends of kamias. Slice into halves, lengthwise. Put on a shallow pan, add onion and tomatoes.
Pour in water and cooking oil, add patis, salt and vetsin.
Arrange galunggong on top of mixtures. Cover and cook for 15 - 20 minutes over low heat.
Add coconut cream. Stir gently so the cream would not curdle. Cook for another 5 minutes.