To make syrup, bring water and sugar together to a boil. Remove from heat and add rosemary. Let sit until cool. Remove rosemary and store syrup refrigerated in a covered jar until ready to use.
In a cocktail shaker add cocktail ingredients along with a handful of ice. Shake for 10 seconds, then pour into martini glass
Notes
Rim martini glass with colored sugar, or lemon zest infused sugar. Wet rim first with a wedge of lemon, then press into sugar.