1.5 oz gin
1.5 oz fresh grapefruit juice
¼ fresh lime
.5 oz thyme simple syrup (see note)
Thyme sprig for garnish
Note: Make thyme simple syrup by combining equal parts sugar and water, heating until sugar melts, then adding fresh thyme leaves and allowing to steep for 1 hour.
Combine all ingredients except club soda and garnish in a cocktail shaker. Shake over ice and strain into a tall, skinny Collins glass, a short tumbler, or a Mason jar filled with ice. Top with club soda and garnish with thyme sprig.