Fill your cocktail shaker about halfway with ice.
Pour in the cranberry juice, orange juice, and simple syrup.
If you want it boozy, add the vodka now.
Shake it up for about 15 seconds until it's good and cold.
Fill a highball glass with fresh ice.
Strain the mix into your glass, filling it roughly two-thirds full.
Top it off with club soda or sparkling water.
Give it a gentle stir with a bar spoon.
Garnish with an orange slice and a few cranberries.
Throw in a rosemary sprig if you want that extra aromatic flair.