Preheat your oven to 400°F (200°C). Spread the peeled and cubed butternut squash on a baking sheet, drizzle with olive oil, and toss to coat evenly.
Place the sliced ginger on the same baking sheet or a separate one. Roast everything in the oven for about 25-30 minutes, until the squash is tender and slightly caramelized, and the ginger is fragrant.
Remove the roasted squash and ginger from the oven and let them cool slightly. Transfer the roasted squash to a large pot, adding the sliced ginger.
Pour in the vegetable broth and bring the mixture to a gentle simmer over medium heat for about 10 minutes, allowing the flavors to meld.
Use an immersion blender or transfer the mixture carefully to a blender, then puree until smooth and velvety. Return the soup to the pot if needed.
Season the soup with salt and black pepper, adjusting to your taste. Warm the soup gently for a few minutes, stirring occasionally.
Serve the soup hot, garnished with a drizzle of olive oil or a sprinkle of fresh herbs if desired.