Place an oven rack at the bottom of the oven and another at the top. Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper.
2. Step
Heat the olive oil in a Dutch oven or large oven-safe pot over medium heat. Add the onion and cook for about 5 minutes, until starting to brown.
3. Step
Add the garlic and rosemary, and cook for 2 minutes, until fragrant.
4. Step
Add the rice and 4 cups (960 ml) of vegetable broth, and stir to combine. Bring to a boil, then cover.
5. Step
Place the risotto on the bottom rack of the oven. Bake for 70 minutes, until all of the liquid has been absorbed by the rice. (It will appear dry, but you’ll be adding moisture back later in the recipe.)
6. Step
Add the butternut squash to the prepared baking sheet. Drizzle with olive oil, then season with salt and pepper. Toss to coat.
7. Step
Place the squash on the top rack of the oven, above the risotto. Bake for 45 minutes, or until the edges of the squash begin to brown and caramelize.
8. Step
Make the fried sage garnish, if using: In a small pot or pan over medium-high heat, add enough olive oil for the sage leaves to sit in. Once hot, carefully place a few leaves into the oil with tongs. Fry for 10-20 seconds, until the leaves are crispy but not browned.
9. Step
Carefully remove from the oil and drain on a paper towel-lined plate. Sprinkle with salt and set aside.
10. Step
Remove the risotto from the oven. Add the remaining vegetable broth, the Parmesan, and butter. Stir until creamy. (The liquid will absorb into the rice as you stir).
