These rum balls are the easiest, best, and most festive cookie to make and gift during the holiday season — they take no time to whip together, require no baking, and are incredibly delicious. What's more? They can be made ahead and frozen, too. Notes: If you can't find vanilla wafers, many people have had success with graham crackers, ginger snaps, shortbread cookies, and even creme-filled cookies. If you'd like to gift rum balls, you may want to pick up a set of Mini Foil Wrappers, which…