In a large saucepan or Dutch oven combine broth, carrots, onion, chili peppers, chili powder, and cumin. Bring mixture to boiling; reduce heat Simmer, covered, 12 minutes or until carrots are very tender.
In a food processor bowl or blender container process half of the mixture until smooth. Repeat with remaining mixture. Return mixture to saucepan. Stir in half-and-half or light cream. Heat through.
To serve, ladle soup into bowls. If desired, garnish with purple basil. Makes 8 side-dish servings.