1. Pour all ingredients into a shaker.
2. Add ice and shake vigorously for 10 seconds.
3. Double strain into a chilled glass.
4. Top with sparkling water.
5. Garnish with a fresh blackberry.

* Ginger syrup:

Bring to a boil equal parts water and sugar with freshly cut ginger (about 12 large pieces). Reduce heat and allow to simmer for 5 minutes, then cover and allow to cool. Remove ginger. Strain into a sterilized jar, cover and refrigerate.