PREPARATION:

1. Heat oil in heavy large pot over medium-high heat. Add carrots and leeks; sauté until leeks begin to soften but not brown, about 5 minutes. Add garlic; sauté 1 minute. Add cumin and crushed red pepper; sauté 30 seconds longer. Add 6 1/2 cups chicken broth. Bring to boil. Reduce heat and simmer uncovered until vegetables are very tender, about 35 minutes.
2. . Working in batches, puree soup in blender until smooth. Transfer soup to large bowl. Cool. Whisk in 6 tablespoons sour cream. Cover soup and refrigerate until cold, at least 4 hours or overnight.
3. Stir lime juice into soup. Thin soup with more broth, if desired. Season with salt and pepper. Ladle into 4 bowls. Spoon 1/2 tablespoon sour cream atop each serving. Sprinkle with cilantro and lime peel.