In a cocktail shaker, combine the gin, rosemary simple syrup, ginger juice, and lemon juice. Add ice and shake until chilled.
Strain the mixture into an ice-filled glass.
Top with club soda.
Garnish with fresh rosemary sprigs.
Serve and enjoy!
Interesting Facts
The rosemary simple syrup in this cocktail is easy to make. Just combine equal parts sugar and water in a saucepan and add fresh rosemary sprigs. Bring to a boil and reduce heat to low. Simmer for 10-15 minutes and let cool. Strain the syrup into a jar and store in the refrigerator.
Ginger juice can easily be made in a blender or food processor. Just peel and chop the ginger and blend until smooth. Strain through a fine-mesh sieve and discard the solids.