First, I lightly clap or press a fresh rosemary sprig with a muddler at the bottom of my cocktail shaker.
This helps release its oils.
I pour in the vodka, fresh grapefruit juice, and simple syrup.
If I prefer my drink more tart, I use less syrup.
Next, I add a handful of ice to the shaker.
I place the lid on tight and shake the mixture for 10-15 seconds.
This chills the drink and mixes the flavors.
Using a fine mesh strainer, I pour the cocktail into a rocks glass filled with fresh ice.
I finish by garnishing with a new rosemary sprig.
Optionally, I add a slice of grapefruit on the rim.
I serve immediately so the drink stays cold and fragrant.