1. In a saucepan over medium heat, heat oil. Add carrots, sweet potato, and onion. Cover and cook, stirring occasionally, until vegetables are softened and brown slightly, about 10 minutes. Add ginger, stir, and cook 1 minute. Add broth, bring to a boil, partially cover, then reduce to a simmer for 10 minutes, or until vegetables are soft.
2. Transfer soup to a blender and puree until smooth. Add coconut water and blend to combine. Return soup to saucepan, add lime juice, curry powder, and cardamom. Stir, then heat through. Garnish with red pepper, pepitas, basil, and green onion, if desired.