In a low ball glass add a small handful of ice and set aside.
To prepare the cocktail:
To a cocktail shaker add light simple syrup, vodka, grand marnier, lemon juice and a handful of ice. Place the lid on and shake vigorously for 20-30 seconds.
Strain over ice into the prepared low ball glass, garnish with a sprig of fresh rosemary and a lemon slice (optional), serve immediately.
Notes
Any simple syrup can be used for this recipe, however I find that light simple syrup will not overpower this cocktail and keeps it light and lemony.