1. Preheat the oven to 200°C (400°F). Peel and seed the squash. Cut into small cubes. Drizzle with oil, season with salt and pepper to taste. Transfer to a baking sheet lined with parchment paper. Roast for 20 minutes, until the squash is tender and golden.
2. Bring the vegetable broth to a boil.
3. Blend ¾ of the roasted squash in a blender with 1 ladle of vegetable broth. Reserve the resulting mixture and the remaining squash cubes warm until ready to use.
4. Heat a pan. Drizzle with oil. Sauté the finely minced onion until tender. Add the rice and sauté for 2 minutes over medium heat. Pour in the white wine and let it evaporate, still over medium heat. Add the saffron (0.1 g). Pour a ladle of simmering vegetable broth over the rice, stirring constantly. When the rice has absorbed the broth, add a second ladle and so on until fully cooked. Stir very regularly. It will take about 20 minutes depending on the type of rice.
5. Towards the end of cooking, pour the hot squash mixture over the rice and mix. Turn off the heat and let the rice rest for a few minutes covered.
6. Serve in shallow bowls. Arrange the squash cubes on top of the risotto. Sprinkle with fresh parsley and season with pepper.