01 - Heat olive oil and 2 tablespoons butter in a large heavy saucepan over medium heat. Add the chopped onion and cook until translucent, about 3 minutes.
02 - Stir in minced garlic and chopped sage leaves; sauté for 1 minute until fragrant.
03 - Add the diced winter squash, season with salt and 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 the dry white wine and simmer, stirring, until mostly absorbed.
06 - Add warm vegetable broth one ladle at a time, stirring constantly and allowing each addition to be absorbed before adding more. Continue until rice is creamy and al dente, about 20 to 25 minutes. You may not need all the broth.
07 - Taste and adjust seasoning. Stir in remaining 1 tablespoon butter, grated Parmesan, and heavy cream if using, until smooth and creamy.
08 - Remove from heat and allow to rest for 2 minutes. Serve garnished with extra sage leaves and additional Parmesan as desired.