Fish Bone Soup

300g fish bones
100g beancurd
50g salted preserved mustard
1 carrot, wedged
1 tomato, wedged
1 tomato, wedged
3 slices old ginger
2 tablespoons oil
1.7 litres (10 cups) water
pinch of salt (optional)

1. Clean and wash the fish bones. Drain. Rinse and drain beancurd.
2. Bring a small pot of water to a boil. Add 2 teaspoons salt and boil the salted preserved mustard for 10 mins. Discard the water and rinse and drain the preserved mustard.
3. Bring 1.6 litres of water to a boil in a clean pot.
4. While the water is being boiled, heat 2 tablespoons of oil in a wok. When the oil is smoking add the slices of old ginger and fry till fragrant. Then add the fish bones and fry till both sides are light goldern brown.
5. Put the fried fish bones and the ginger into boiling water. Also add the beancurd, preserved mustard and carrot.
6. Cover the pot and boil over high heat for 15 mins and then bring the heat to low to simmer. After 1 and half hours, add tomato wedges and simmer for another hour.
7. Taste and add salt if required.
8. Please sieve the soup stock before feeding the soup to young children.