Melt the coconut oil in a large saucepan over a low/medium heat. Finely dice the onion and chili, grate the ginger and crush the garlic. Add to the saucepan and sweat gently for 3-4 minutes until tender and fragrant.
Add the cauliflower florets to the saucepan along with the curry powder, turmeric and cumin. Stir well to combine. Pan fry for 3-4 minutes to soften the cauliflower a little.
Add the coconut milk and vegetable stock to the saucepan. Stir well. Bring to a gentle boil, then simmer for 6-7 minutes until the cauliflower is fork tender.
Carefully transfer the soup to a blender or use a hand held stick blender and process until smooth. Divide between four serving bowls. Scatter with chopped fresh cilantro and optionally fresh chili to serve.