Preheat your oven to 400°F (200°C).

In a large bowl, toss the chopped carrots and onion with olive oil, salt, and pepper until well coated.

Spread the vegetables in a single layer on a baking sheet. Roast in the preheated oven for 25-30 minutes, or until the carrots are tender and slightly caramelized.

In a large pot, combine the roasted carrots and onion with grated ginger and vegetable broth. Bring to a simmer over medium heat.

Use an immersion blender to puree the soup until smooth. Alternatively, transfer the soup in batches to a blender and blend until smooth.

Stir in the coconut milk and lemon juice. Heat through for an additional 5 minutes.

Taste and adjust seasoning if needed. Serve hot, garnished with fresh cilantro or parsley if desired.