1.In large saucepan, heat oil; cook onion and garlic, stirring constantly, until onion softens.
2.Add stock and the water to onion mixture; bring to a boil. Reduce heat, add chicken; simmer, uncovered, about 5 minutes or until chicken is cooked through.
3.Add both corns, and cornflour blended with the extra water; cook, stirring, until mixture boils and thickens slightly. Gradually add egg, in a thin stream to simmering soup. Serve soup sprinkled with green onion.