Preparation Melt butter in heavy large saucepan over medium-high heat. Add squash, leeks, carrot and celery; sauté until slightly softened, about 15 minutes. Mix in apples, thyme and sage. Add stock and 1 cup cider and bring to boil. Reduce heat to medium-low. Cover and simmer until apples are tender, stirring occasionally, about 30 minutes. Cool slightly. Working in batches, purée soup in blender. Return soup to pan. Boil remaining 1/2 cup cider in heavy small saucepan until reduced to 1/4 cup, about 5 minutes. Cool. Place sour cream in small bowl. Whisk in reduced cider. (Soup and cider cream can be made 1 day ahead. Cover separately and refrigerate.) Bring soup to simmer. Mix in whipping cream. Ladle soup into bowls. Drizzle with cider cream. Top with chives.
Preparation Melt butter in heavy large saucepan over medium-high heat. Add squash, leeks, carrot and celery; sauté until slightly softened, about 15 minutes. Mix in apples, thyme and sage. Add stock and 1 cup cider and bring to boil. Reduce heat to medium-low. Cover and simmer until apples are tender, stirring occasionally, about 30 minutes. Cool slightly. Working in batches, purée soup in blender. Return soup to pan. Boil remaining 1/2 cup cider in heavy small saucepan until reduced to 1/4 cup, about 5 minutes. Cool. Place sour cream in small bowl. Whisk in reduced cider. (Soup and cider cream can be made 1 day ahead. Cover separately and refrigerate.) Bring soup to simmer. Mix in whipping cream. Ladle soup into bowls. Drizzle with cider cream. Top with chives.