Preheat the oven to 400°F (200°C). Spread the cubed butternut squash on a baking sheet, drizzle with a tablespoon of olive oil, and sprinkle with a pinch of salt. Roast for about 25-30 minutes until golden and caramelized, then set aside.
In a large saucepan, heat the remaining tablespoon of olive oil over medium heat. Add the finely chopped onion and cook gently, stirring often, until translucent and soft—about 5 minutes. Add the minced garlic and cook for another minute until fragrant.
Add the arborio rice to the saucepan and stir well to coat each grain with the oil and aromatics. Cook for 1-2 minutes until the edges of the rice look slightly translucent and it begins to toast lightly.
Pour in a ladle of warm vegetable broth, stirring constantly. Wait until the liquid is mostly absorbed before adding another ladle. Continue this process, adding broth gradually and stirring, until the rice is creamy and just tender—about 20 minutes.
Stir in the roasted butternut squash chunks and chopped spinach. Cook for another 2-3 minutes until the greens are wilted and the squash is heated through.
Finish with a tablespoon of butter, stirring until melted and the risotto is creamy. Season with salt and pepper to taste.
Serve the risotto hot, garnished with additional spinach or herbs if desired. Enjoy the rich, velvety texture and seasonal flavors in every bite!