In a large container, add the whiskey, rock candy, clove, and horehound. Allow to infuse in a cool, dark place for about three days. Add the remaining ingredients and steep for an additional one to two days, or longer to taste. Once the whiskey has reached desired flavor, strain out the fruits and spices and bottle the whiskey.
Tips: Use a good rye whiskey; mid-range bottles work perfectly. The longer the rock candy sits, the more the flavors meld. Test periodically until desired flavor intensity. Bottle under a tight seal. Keeps up to two months in refrigerator.
Variations: Use orange slices instead of lemon or both; add pineapple chunks or honey/syrup instead of rock candy. Adjust sweetness to taste.