01 - Heat the vegetable broth in a medium saucepan and keep warm over low heat.
02 - Melt 2 tablespoons butter in a large skillet or Dutch oven over medium heat. Add onion and cook until soft and translucent, about 3 minutes.
03 - Add minced garlic and cook 1 minute. Stir in diced winter squash and cook until it starts to soften, about 5 minutes.
04 - Add Arborio rice and chopped sage, stirring for 2 minutes until rice is coated and slightly translucent.
05 - Pour in white wine and cook, stirring, until mostly absorbed.
06 - Ladle warm broth into rice mixture one cup at a time, stirring frequently. Allow liquid to absorb before adding more. Continue until rice is creamy and tender and squash is cooked, about 20–25 minutes.
07 - Remove from heat. Stir in remaining 1 tablespoon butter, Parmesan cheese, and heavy cream if using. Season with salt and pepper to taste.
08 - Plate immediately, garnishing with additional Parmesan and fresh sage if desired.