Place apples in a 4-quart stock pot with the Riesling, Calvados and all remaining ingredients EXCEPT the cream and yogurt. Bring to a boil; reduce to a simmer and cook for 20 - 30 minutes. Remove from heat. Force contents of pot through strainer. Puree ingredients that remain in strainer and add to the liquid. Chill soup over ice.
Whisk in yogurt and cream and serve in iced bowls.