Sweet corn & chicken soup

This is the first recipe that I've tried from my newest cookbook, Simple Chinese Cooking written by Kylie Kwong, and man was it ever good. To make the soup you need:

• 4 cobs sweet corn
  
• 1 small white onion
• 1 garlic clove
• 5 cm knob ginger
• 2 tablespoons vegetable oil
• 1 teaspoon sea salt
• 1/2 cup shao hsing wine or dry sherry
• 7 cups chicken stock
• 200g chicken breast cut widthways into 1 cm slices
• 2 teaspoons soy sauce
• 2 egg, lightly beaten
• 1 finely sliced spring onion

Her directions for making the soup are as follows:

1. Remove kernels from corn cobs by running a sharp knife down the sides of each cob - you should have about 3 cups of corn kernels. Peel and finely dice onion and garlic. Peel ginger and cut into thin slices and then into fine strips (julienne) - you should have about 2 tablespoons ginger julienne.
2. Heat oil in a medium sized heavy based pot and saute onion, ginger, garlic, and salt for 1 minute. Add wine or sherry and simmer for a further minute or until liquid has reduced by half. Stir in corn and stock and bring to the boil. Reduce heat and simmer gently for 30 minutes. During the cooking time you may need to skim the surface of the soup to remove any impurities.
3. Stir through chicken and soy sauce and simmer for a further minute. Lower heat and slowly pour in beaten egg into soup in a thin stream, stirring constantly with a fork. Remove the soup from the stove as soon as you see the egg forming fine "ribbons".
4. Serve soup in bowls and garnish with spring onions.