Preheat the oven to 400°F (200°C). Arrange the butternut squash chunks on a baking sheet, drizzle with a tablespoon of olive oil, and toss to coat. Roast for about 25-30 minutes until tender and slightly caramelized.
While the squash roasts, heat the remaining olive oil in a large pot over medium heat. Add the chopped shallot and cook, stirring frequently, for about 3-4 minutes until softened and fragrant.
Add the grated ginger to the shallots and cook for another minute, allowing the spices to release their aroma.
Once the squash is roasted and cool enough to handle, add it to the pot with the sautéed aromatics. Pour in the vegetable broth and bring to a gentle simmer.
Use an immersion blender or transfer the soup in batches to a blender, then blend until smooth and creamy. Return the soup to the pot if transferred, and stir in coconut milk if using.
Season the soup with salt and pepper to taste. Warm gently over low heat, stirring occasionally, until heated through.
Serve the soup hot, garnished with additional ginger slices or a swirl of coconut milk if desired, and enjoy its velvety, vibrant texture.
