Make the madras paste by grinding the coriander and cumin seeds in a pestle and mortar until reduced to a fine powder (or grind in a coffee grinder)
Add the other spices, then stir in the vinegar
Heat the oil in a small pan and gently cook the spice mix for 3 minutes, stirring frequently, until just beginning to bubble
Allow to cool, stir well and store in an airtight container in the fridge for up to 1 month
For the Soup
Fry the shallots and celery in a large saucepan over a gently heat until beginning to soften - about 5 minutes
Add the carrot and parsnip and fry for 3 more minutes. Stir in the madras paste and allow to cook for 1 more minute
Place the chicken in the saucepan and pour over 750ml/ 3 cups of the stock. Bring to the boil, cover and simmer for 30 minutes (or until the chicken is cooked)
Remove the chicken and allow to cool slightly, then shred using 2 forks to rip it apart
Add the pepper and passata to the soup, season to taste and bring to the boil. Cook for 5 minutes, adding extra stock to loosen the soup if needed
Return the chicken to the pan, along with the potato and rice. Heat through and serve, garnished with fresh coriander
Notes
If you make the curry paste, you will end up with more than enough for this recipe. It keeps well in an airtight container for up to 1 month in the fridge, ready to make a second batch of soup or try adding it to your favourite curry recipe.