Preparation Preheat oven to 450°F. Keeping husks on corn, place corn on heavy rimmed baking sheet. Roast until corn is fragrant and husks brown, about 30 minutes. Let cool. Remove husks from corn. Cut off corn kernels and set aside. Char chili over gas flame or in broiler until blackened on all sides. Enclose in paper bag and let stand 10 minutes. Peel, seed and quarter chili. Combine 3 1/2 cups water, broth and potato in large pot. Cover partially and simmer over medium heat until potato is tender, about 20 minutes. Using slotted spoon, transfer potato to processor; reserve cooking liquid. Add corn, chili and chopped cilantro to processor. Puree until mixture is as smooth as possible, gradually adding most of reserved cooking liquid through feed tube. Strain corn puree through sieve into large saucepan, pressing on solids. Mix in remaining cooking liquid and cream. (Can be prepared 1 day ahead. Cover and refrigerate.) Bring soup to simmer. Season to taste with salt and pepper. Ladle soup into bowls. Garnish with cilantro sprigs and then serve immediately.
Preparation Preheat oven to 450°F. Keeping husks on corn, place corn on heavy rimmed baking sheet. Roast until corn is fragrant and husks brown, about 30 minutes. Let cool. Remove husks from corn. Cut off corn kernels and set aside. Char chili over gas flame or in broiler until blackened on all sides. Enclose in paper bag and let stand 10 minutes. Peel, seed and quarter chili. Combine 3 1/2 cups water, broth and potato in large pot. Cover partially and simmer over medium heat until potato is tender, about 20 minutes. Using slotted spoon, transfer potato to processor; reserve cooking liquid. Add corn, chili and chopped cilantro to processor. Puree until mixture is as smooth as possible, gradually adding most of reserved cooking liquid through feed tube. Strain corn puree through sieve into large saucepan, pressing on solids. Mix in remaining cooking liquid and cream. (Can be prepared 1 day ahead. Cover and refrigerate.) Bring soup to simmer. Season to taste with salt and pepper. Ladle soup into bowls. Garnish with cilantro sprigs and then serve immediately.