Preheat oven to 400°F (200°C).

In a large bowl, toss butternut squash, carrot (if using), and onion with olive oil, salt, and pepper.

Spread vegetables in a single layer on a baking sheet.

Roast for 30-40 minutes, or until vegetables are tender and slightly caramelized.

In a large pot or Dutch oven, combine roasted vegetables, vegetable stock, and maple syrup.

Bring to a boil, then reduce heat and simmer for 10-15 minutes.

Carefully transfer the soup to a blender (or use an immersion blender) and blend until smooth and creamy.

Stir in coconut milk and adjust seasoning to taste.

Serve hot.