Preheat oven to 200 C / Gas 6. Line a baking tray with foil. Roast pumpkin until tender, about 45 minutes.
Combine pumpkin, coconut drink, chicken stock, cinnamon, ginger, cloves, sage and salt in a stockpot and bring to the boil. Reduce heat and simmer for 5 minutes. Blend soup using an immersion blender until smooth. Serve with a dollop of yogurt, if desired, and a sprinkling of nuts.