This would be delicious with brunch!

3 oz. Gin
3 oz. Grapefruit Juice
1 oz. Simple Syrup
2 oz. Club Soda

In a cocktail shaker filled with ice, add the gin, grapefruit juice and simple syrup. Shake well and strain into a glass with fresh ice.  Top off with club soda and stir with a bar spoon.  Garnish with a sprig of rosemary and wedge of grapefruit if desired.  Cheers!