01 - Preheat oven to 400°F. Toss diced butternut squash with 1 tablespoon olive oil, salt, and pepper. Spread evenly on a parchment-lined baking sheet and roast for 20 to 25 minutes until tender and lightly caramelized.
02 - In a large saucepan or Dutch oven, heat remaining 1 tablespoon olive oil and 1 tablespoon butter over medium heat. Add onion and cook until softened, about 3 to 4 minutes, then add minced garlic and cook for 1 additional minute.
03 - Stir in Arborio rice and cook for 2 minutes, stirring constantly to coat grains in oil and butter.
04 - Pour in dry white wine and cook, stirring, until nearly fully absorbed by the rice.
05 - Add warm vegetable broth one ladle at a time, stirring frequently and allowing each addition to be absorbed before adding the next, until rice is creamy and just tender, approximately 18 to 20 minutes.
06 - Stir roasted butternut squash, chopped sage, and remaining 2 tablespoons butter into the risotto. Cook for 2 to 3 minutes to warm through.
07 - Remove from heat. Incorporate Parmesan cheese and heavy cream if using. Adjust seasoning with salt and freshly ground black pepper according to taste.
08 - Plate risotto hot, garnished with additional fresh sage and, if desired, extra grated Parmesan.