- Heat a large saucepan or casserole dish, pour in the olive oil, then add the onion, celery, chilli and coriander seeds. 
- Season to taste then cook, stirring occasionally, for about 10 minutes until the onion has turned silky soft and translucent. Add the garlic and potato and cook for a further few minutes, stirring to coat the potato in oil before finally adding the cauliflower and enough stock or water to cover. 
- Simmer the broth until the cauliflower is completely tender. Whizz up with a stick blender and taste to check the seasoning, adding more salt and pepper if you think it needs it.