Chicken Soup with Apples and Leeks

This full-flavored winter soup balances the sweetness of apples and the tang of cider vinegar against an earthy background of gently simmered leeks. The flavor of the apples can be accentuated by adding a tiny amount of Calvados (see box) just before serving, but the soup is still wonderful without it. Instead of disguising the flavor of the chicken, the apples and leeks seem to accentuate it and bring it into focus. This delicious soup never fails t