1. Pour all ingredients into a shaker.
2. Shake vigorously first without ice (dry shake) for 10 seconds.
3. Add ice cubes and shake vigorously another time for 10 seconds.
4. Double filter using a fine strainer into a glass with ice.
5. Garnish with a basil leaf.
* Simple syrup is equal parts sugar and water. Dissolve sugar in a saucepan over medium heat. Strain into a sterilized jar and seal tightly with a lid.