Preheat your oven to 200°C (400°F). Place the peeled pumpkin pieces on a roasting pan, drizzle with a tablespoon of olive oil, and roast for about 30 minutes until deeply golden and soft.
Once roasted, let the pumpkin cool slightly, then mash or chop into small, tender pieces. Set aside.
Heat the broth in a small pot over low heat to keep it warm throughout the cooking process.
In your large heavy-bottomed pot, melt the butter with a tablespoon of olive oil over medium heat until fragrant, about 1-2 minutes.
Add the finely chopped onion and sauté for about 5 minutes until translucent and soft, filling your kitchen with a sweet aroma.
Add the arborio rice to the onions, stirring constantly for 2 minutes until the rice is slightly toasted and translucent at the edges.
Begin adding the warm broth one ladleful at a time, stirring gently but constantly. Wait until each addition is mostly absorbed before adding the next, allowing the rice to release its creamy starch.
Continue this process until the rice is tender yet still has a slight bite, about 20-25 minutes. The risotto should be creamy and thick enough to coat the back of a spoon.
Stir in the caramelized pumpkin pieces, mixing well to evenly distribute the sweetness and texture. Add the cream or coconut milk if using, for extra richness.
Once everything is heated through, remove from heat and stir in the grated Parmesan and a pinch of nutmeg, adjusting seasoning as needed.
Finish with a drizzle of good olive oil, then serve immediately, garnished with additional Parmesan if desired. Enjoy the cozy, caramel-rich flavors of this pumpkin risotto.