01 - Heat the olive oil and 2 tablespoons of butter in a large heavy saucepan over medium heat. Add the chopped onion and cook until translucent, about 3 minutes.
02 - Stir in the minced garlic and chopped sage leaves; sauté for 1 minute until fragrant.
03 - Add the diced winter squash, season with salt and black pepper, and cook for 5 minutes, stirring occasionally.
04 - Incorporate the Arborio rice and cook for 2 minutes, stirring to toast the grains lightly.
05 - Pour in the white wine and simmer, stirring continuously until it is mostly absorbed by the rice.
06 - Add warm vegetable broth one ladleful at a time, stirring constantly and allowing each addition to be absorbed before adding the next. Continue this process until the rice is creamy and al dente, approximately 20 to 25 minutes.
07 - Adjust seasoning to taste. Stir in the remaining 1 tablespoon of butter, grated Parmesan, and heavy cream if using, blending until smooth and creamy.
08 - Remove from heat and let rest for 2 minutes. Serve garnished with extra sage leaves and additional Parmesan if desired.