Heat the broth. Add the duck meat, corn kernels and corn water. Season with salt and pepper. Bring to the boil, lower the heat, cover and simmer for about ten minutes to allow the sweet corn water and the duck broth to come together.
Add the shredded cabbage and simmer for another ten minutes.
Turn off the heat. Pour in the beaten egg in a thin stream. No dot stir for about ten seconds to allow them to partially set. Then, stir the soup.
Ladle the soup into bowls, garnish with onion leaves and toasted garlic bits.