1. Preheat oven to 200°C. Toss the cauliflower with enough coconut oil to lightly coat. Spread the cauliflower in a single layer on a large baking sheet and roast until the tips of the cauliflower are golden brown, about 25 to 30 minutes.
2. Heat a large heavy-bottomed pan over a medium heat with the rest of the oil (about 1 tbsp). Sweat the onion until translucent, about 3 minutes. Stir in the curry paste and turmeric. Raise the heat to medium-high, add the wine, and cook, stirring frequently until most of the wine has evaporated.
3. Add 3/4 of the cauliflower florets and all the stems into the pan. Add the stock, coconut milk and sugar. Cook, stirring occasionally, until the soup is warmed through. Stir in the vinegar and lime juice to taste. Remove from heat.
4. Use a hand blender or transfer the soup in small batches into a food processor and process until smooth. Be careful of the steam escaping from the lid. You may need to add a little more stock or water depending on the how you like the consistency of the soup.
5. Season to taste. Ladle the soup into bowls. Top with some of the roasted cauliflower florets and a sprinkle of chives before serving.