The Rosemary Gin & Tonic is a winter cocktail that was created by the editors of PUNCH and was first published in their book Winter Drinks: 70 Essential Cold-Weather Cocktails. Just as its name implies, this is a seasonal variation of the Gin & Tonic that is made with gin, citrus, and tonic water, but it adds in a vinegar-based grapefruit shrub for more complex, savory flavor.
Stem one rosemary sprig.
Add rosemary leaves and grapefruit shrub to a shaker.
Using a muddler, gently muddle for 5-7 seconds.
Add gin and lime juice to shaker.
Fill shaker with cubed ice.
Shake for 10-20 seconds.
Fill a highball glass with fresh cracked ice.
Using a Hawthorne and fine mesh strainer, strain into highball glass.
Top with tonic water.
Garnish with grapefruit slices and remaining rosemary sprig.