1 cup (8 ounces) unsweetened pink grapefruit juice
2 tbsp Rosemary Simple Syrup
Place water, sugar and rosemary in a small saucepan and simmer until sugar dissolves. Let steep for 23 hours, then strain into a clean jar. Simple syrup may be stored in refrigerator (in a jar with a tight fitting lid) up to 2 weeks.
Combine gin, grapefruit juice and 2 tablespoons Rosemary Simple Syrup in a shaker with ice. Shake well and strain into martini glasses. If desired, garnish with a sprig of fresh rosemary.