Preheat your oven to 400°F (200°C). Toss the diced butternut squash in a bowl with olive oil, salt, and pepper. Spread it on a baking sheet and roast for 25-30 minutes until tender.

While the squash roasts, warm the vegetable broth in a saucepan over low heat and cover to maintain warmth.

In a large skillet, heat olive oil over medium heat. Sauté the chopped onions for 4-5 minutes until translucent, then add garlic and cook for 1 more minute.

Add Arborio rice to the skillet, stirring to coat in oil. Toast the rice for 2 minutes until edges are translucent.

Pour in a ladleful of warm broth, stirring continuously. Allow it to absorb before adding more, repeating this for about 20 minutes.

Once risotto is creamy, fold in roasted butternut squash, grated Parmesan, and chopped sage. Stir until combined and adjust seasoning with salt and pepper.