Either use a channel knife to make a long strip of lemon peel, or cut a round slice of lemon and cut the rind off of the inside part.
Add three fresh cranberries to a cocktail pick.
Wrap the lemon peel around the cranberries and set the garnish aside.
Cocktail
Add the lemon juice, syrup, cranberry juice and whiskey to a cocktail shaker.
Fill the shaker with ice.
Seal up the shaker and give it about 15-20 vigorous shakes.
Add ice to your serving glass and strain in the drink.
Top it off with your prepared garnish, and serve. Cheers!
Notes
You can garnish with just a lemon slice if you don't have fresh cranberries.
If you can't find 100% cranberry juice, you can use a "cranberry cocktail" or something like Cran-Apple juice. You just will need to reduce the amount of simple syrup, because they will be less tart than the all-cranberry juice. Try using just half the simple syrup called for in the recipe, and then add more if you need more sweetness.
If you want a foamy layer on top, you can add in Fee Foam, or use 1 ounce of pasteurized egg whites in the drink. Shake it for about a minute without ice to develop a foam, before shaking again with ice.