01 - Heat olive oil and 2 tablespoons butter in a large heavy saucepan over medium heat. Add finely chopped onion and cook until translucent, approximately 3 minutes.
02 - Stir in minced garlic and chopped sage leaves; sauté for 1 minute until fragrant.
03 - Add diced winter squash, season with salt and black pepper, and cook for 5 minutes, stirring occasionally.
04 - Stir in Arborio rice and cook for 2 minutes to lightly toast the grains.
05 - Pour in dry white wine and simmer, stirring, until mostly absorbed by the rice.
06 - Add warm vegetable broth one ladle at a time, stirring constantly and allowing each addition to absorb before adding the next. Continue this process for 20 to 25 minutes until the rice is creamy and al dente; you may not need all the broth.
07 - Adjust seasoning to taste. Stir in remaining 1 tablespoon butter, grated Parmesan, and heavy cream if using, mixing until smooth and creamy.
08 - Remove from heat, let rest for 2 minutes, then serve garnished with additional sage leaves and extra Parmesan as desired.