Preheat the oven to hot (220°C). Combine the pumpkin with half the oil in a baking dish. Bake, uncovered, in a hot oven for about 20 minutes or until tender.
Meanwhile, combine the stock and water in a large saucepan. Bring to the boil then reduce the heat to simmer.
Heat the remaining oil in a large saucepan; cook the onion and garlic, stirring, until onion is soft. Add rice; stir to coat in oil mixture. Add the wine, stir until almost evaporated.
Stir in one cup (250ml) of the hot stock mixture; cook, stirring, over low heat until liquid is absorbed. Continue adding the stock mixture, in one-cup batches, stirring until liquid is absorbed after each addition. Total cooking time should be about 25 minutes or until rice is just tender.
Add spinach, pine nuts, cheese, cream and salt and pepper to taste; cook, stirring, until the spinach is wilted. Gently stir in pumpkin.
Serve topped with extra parmesan cheese flakes.
Tip: Pumpkin can be roasted several hours ahead. The risotto is best made just before serving.