01 - Preheat the oven to 425°F.
02 - Toss carrots, onion, and garlic with 1 tablespoon olive oil, 1/2 teaspoon salt, and black pepper on a baking sheet; roast for 25 to 30 minutes, turning halfway through, until tender and caramelized.
03 - Heat remaining tablespoon olive oil in a large pot over medium heat; add ginger, cumin, and coriander and sauté for 1 to 2 minutes until fragrant.
04 - Add roasted vegetables to the pot; pour in vegetable broth and bring to a boil, then reduce heat and simmer for 10 minutes.
05 - Stir in coconut milk, reserving 2 tablespoons for garnish; simmer an additional 5 minutes.
06 - Remove from heat and purée soup using an immersion blender or in batches with a standard blender until silky smooth.
07 - Stir in lime juice; taste and adjust salt as needed.
08 - Ladle soup into bowls; swirl in reserved coconut milk and garnish with fresh herbs if desired.