Peel and chop the onion, turmeric and ginger. Peel the root vegetables and cut them into bite-sized chunks. Tear the cauliflower into chunks.
Heat the oil in a pot over a medium heat then add the onions. Stir for about 5 minutes to soften. Add the spices, chopped turmeric and ginger, then stir for a minute.
Put in the vegetable chunks and stir to coat them well in the spices.
Pour in the stock, add the bay leaf and bring to the boil.
Add the cauliflower, bring to the boil again, then simmer for about 20 minutes, covered, over low heat or until the vegetables are tender.
Remove the bay leaf and add the fresh herbs.
Whiz, using a hand-held blender, into a textured or smooth soup, according to your liking.
Serve warm.