For the stock: Put all the stock ingredients into a saucepan and bring to the boil. Simmer until the vegetables are tender, then remove the bouquet garni and star anise.
Meanwhile: Place all the soup ingredients into a roasting tin. Cover with tin foil and cook for 30 minutes or until the fruit and vegetables are soft and tender.
Once the stock and the roasted vegetables are done add the contents of the roasting tin to the stock along with another approximately 2 to 3 pints of water (enough to make about 4 pints of soup) and blend until smooth.
Add 2 generously heaped tablespoons of horseradish sauce (from a jar) and blend again.
Taste and add more horseradish and seasoning if required.