Preheat oven to 400°F. Toss butternut squash cubes with 1 tablespoon olive oil, salt, and pepper. Spread on a baking sheet and roast for 30-35 minutes until tender and lightly caramelized.

In a large pot, heat remaining olive oil over medium heat. Add diced onion and cook for 5 minutes until softened. Add garlic and ginger, cooking for another minute until fragrant.

Add the roasted butternut squash to the pot along with the vegetable broth. Bring to a simmer and cook for 10 minutes to allow flavors to meld.

Using an immersion blender, puree the soup until completely smooth. Alternatively, carefully transfer to a blender in batches and blend until creamy.

Stir in the coconut milk and nutmeg if using. Heat through for 2-3 minutes, adjusting seasoning with additional salt and pepper to taste.

Ladle soup into bowls and garnish with a drizzle of coconut milk, toasted pepitas, or fresh herbs if desired. Serve hot.