Instructions

1. Preheat the oven to 200°C/390°F.
2. Peel the pumpkin and sweet potatoes and chop them into large chunks, about 5 cm (2 inches) in size.
3. Peel the onion and cut it into quarter wedges.
4. Place the vegetables onto a large baking tray.
5. Drizzle the olive oil over the vegetables, and sprinkle over the ground cinnamon and freshly ground nutmeg.
6. Roast the vegetables for about 1 hour until they are golden and cooked through.
7. When the vegetables are nearly done, bring the vegetable or chicken stock to the boil.
8. Place the roasted vegetables into a large saucepan, and pour over just enough stock to cover the vegetables.
9. Bring the saucepan to a gentle simmer.
10. Take the saucepan off the heat.
11. Use a stick blender to purée the soup. Alternatively, purée the vegetables with some stock in a blender, though you will have to do this in a few batches.
12. If the soup is a bit thick, add some more stock or hot water to thin out the soup to your liking.
13. Heat the soup until it is gently simmering and taste for seasoning.