Roast the Squash: Preheat the oven to 400°F (200°C). Drizzle the butternut squash halves with olive oil, then place them cut side down on a baking sheet. Roast for 30-40 minutes or until tender. Remove from the oven, let cool slightly, and scoop out the flesh.

Sauté the Aromatics: In a large pot, heat a tablespoon of olive oil over medium heat. Add the diced onion and sauté until translucent, about 5 minutes. Add the garlic, curry powder, cumin, turmeric, and ginger, and cook for another 1-2 minutes, until fragrant.

Add Squash and Broth: Add the roasted squash flesh to the pot, stirring to combine with the spices. Pour in the vegetable broth, then bring the soup to a boil. Reduce the heat to low and let it simmer for 15-20 minutes.

Blend the Soup: Use an immersion blender to purée the soup until smooth. Alternatively, carefully transfer the soup in batches to a blender and blend until smooth.

Season and Serve: Season with salt and pepper to taste. Serve hot, garnished with a sprinkle of fresh herbs or a swirl of coconut milk if desired.

Enjoy your cozy, flavorful soup!