Preparation Using cleaver or heavy large knife, cut each ear of corn crosswise in half. Place corn in heavy large pot. Add 5 cups broth, shallots, and onion; bring to boil. Reduce heat, cover, and simmer until corn is very tender, about 25 minutes. Using tongs, transfer corn to large bowl to cool; reserve broth. Cut corn kernels off cobs. Return 4 cups corn kernels to broth (reserve any remaining corn for another use). Working in batches, puree soup in blender until very smooth. Strain soup through fine sieve set over large bowl, pressing on solids with back of spoon; discard solids. Mix in enough additional chicken broth to thin soup to consistency of heavy cream. Season to taste with salt and pepper. Cover and refrigerate soup until cold, about 4 hours. (Can be made 1 day ahead. Keep refrigerated.) Ladle soup into 6 bowls. Top each with dollop of crème fraîche. Sprinkle with cucumber and chives and serve.
Preparation Using cleaver or heavy large knife, cut each ear of corn crosswise in half. Place corn in heavy large pot. Add 5 cups broth, shallots, and onion; bring to boil. Reduce heat, cover, and simmer until corn is very tender, about 25 minutes. Using tongs, transfer corn to large bowl to cool; reserve broth. Cut corn kernels off cobs. Return 4 cups corn kernels to broth (reserve any remaining corn for another use). Working in batches, puree soup in blender until very smooth. Strain soup through fine sieve set over large bowl, pressing on solids with back of spoon; discard solids. Mix in enough additional chicken broth to thin soup to consistency of heavy cream. Season to taste with salt and pepper. Cover and refrigerate soup until cold, about 4 hours. (Can be made 1 day ahead. Keep refrigerated.) Ladle soup into 6 bowls. Top each with dollop of crème fraîche. Sprinkle with cucumber and chives and serve.