Preheat the oven to 200 degrees. Remove the outer leaves and chop the cauliflower into bite-size florets. Place on a large baking tray. Peel and quarter the onion and place on the tray with the cauliflower. Drizzle everything with one to two tablespoons of olive oil and roast until tender when pierced with a fork and just browning at the edges – about 15 minutes.

In batches, blitz the roast vegetables with the ginger and coconut milk until silky smooth. This is best done in a blender for a creamy result. Pour the thick mixture into a saucepan and add the stock. Heat gently and add salt to taste before serving.