Heat 2 tablespoons of olive oil in a large frying pan over medium heat. Once hot, add the onion to the pan. Cook, stirring often for 3-4 minutes, or until the onions have softened.
Add 1 ladle (approximately ½ cup) of the vegetable broth to the pan. Let the onion cook for 2 minutes in the broth to soften further. Add the garlic and cook for 1 minute.
Add the arborio rice to the pan along with 2 tablespoons of olive oil. Toast, stirring often for 2 minutes, or until the edges of the rice begin to turn translucent.
Add ½ cup of wine to the pan and stir until the wine absorbs into the rice. Reserve the remaining wine for later.
Add ½ cup of vegetable broth to the pan at a time, stirring until all the broth has been absorbed. Continue this process until all the broth has been added, this should take 15 to 20 minutes.
As the risotto is cooking, remove the skin from the butternut squash and cut into 1-cm cubes. Set aside.
After 20 minutes, add the remaining ½ cup of wine, followed by the butternut squash, nutmeg, and Parmesan cheese. Stir to combine.
Taste the rice—it should be tender but still have a bit of a bite in the center. Turn the heat to low to keep warm.
In a separate frying pan, heat the butter and the remaining 2 tablespoons of olive oil over high heat. Once hot, add the sage leaves and cook for 2-3 minutes until crispy.
Place the risotto in serving bowl and garnish with extra parmesan cheese, brown butter, and sage leaves. Serve immediately and enjoy!