Combine rye whiskey, apple cider, lemon juice and simple syrup in a cocktail shaker with ice. Shake for about 10 seconds and pour into a glass with ice.
For a festive fall presentation garnish with an apple slice or cinnamon stick.
Notes
Note that I'm listing simple syrup as optional. Depending on the sweetness of the apple cider, you may not need to add the simple syrup. On the other hand you may want a 1/2 ounce to 1 ounce of simple syrup to find that perfect balance of sweet and sour.