1.
Heat half the oil in a large pan over a medium heat and stir in the celeriac and parsnips until well coated. Season with a pinch of salt and plenty of pepper. Sauté for 8-10 minutes until just starting to pick up a bit of colour.
2.
Sprinkle over the curry powder and turmeric and continue to sauté for 1 minute.
3.
Pour the stock into the vegetable mixture and bring to a simmer. Season again generously with the pepper and simmer for another 10 minutes until the vegetables are completely tender.
4.
Meanwhile, heat a small non-stick frying pan over a medium heat. Add the cumin seeds and toast for 30 seconds to 1 minute until fragrant. Stir into the remaining tablespoon of olive oil and set aside until needed.
5.
Blitz the soup with a hand blender until smooth, adding a little water if you think that the texture is too thick, then reheat if necessary. Ladle the soup into warmed bowls and drizzle over the cumin oil and scatter with the coriander, if liked to serve.