01 - Preheat oven to 400°F. Toss squash cubes with 1 tablespoon olive oil, a pinch of salt, and pepper. Spread on a baking sheet and roast for 20–25 minutes, stirring once, until tender and lightly caramelized. Set aside.
02 - In a large, heavy-bottomed saucepan, heat the remaining 1 tablespoon olive oil and 1 tablespoon butter over medium heat. Add the onion and cook until softened, about 3 minutes. Stir in the garlic and sage, cooking for another minute until fragrant.
03 - Add the Arborio rice, stirring to coat each grain with the oil and butter. Toast for 1–2 minutes, until the edges look translucent.
04 - Pour in the white wine, stirring until completely absorbed.
05 - Add the warm broth one ladle at a time, stirring frequently. Wait until most of the liquid is absorbed before adding more. Continue until the rice is creamy and al dente, about 18–20 minutes.
06 - Gently fold in the roasted squash. Remove from heat and stir in the remaining 2 tablespoons butter and the Parmesan cheese. Season with additional salt and pepper to taste.
07 - Serve immediately, garnished with extra sage and a sprinkle of Parmesan.