Preheat the oven to 400°F (200°C). Spread the chunks of butternut squash on a baking sheet, drizzle with olive oil, and toss to coat. Roast in the oven until tender and slightly caramelized, about 25-30 minutes.
While the squash roasts, heat a tablespoon of olive oil in a large soup pot over medium heat. Add the diced onion and cook until translucent and fragrant, about 5 minutes. Stir occasionally to prevent burning.
Add the minced ginger to the onions and cook for another minute, allowing the aroma to deepen and the ginger to soften.
Once the roasted squash has cooled slightly, transfer the chunks into the soup pot. Pour in the vegetable broth and bring to a gentle simmer.
Simmer the mixture for about 10 minutes, allowing flavors to meld and the squash to soften further.
Use an immersion blender to carefully blend the soup until perfectly smooth and creamy, or transfer in batches to a blender and purée until smooth.
Taste the soup and season with salt and pepper as needed, then give it a final stir to incorporate.
Serve the soup hot, garnished with a swirl of cream or a sprinkle of fresh herbs if desired. Enjoy the warm, velvety texture and vibrant color with every spoonful.
