In a 2 pint jar, muddle together the ginger, sugar, and rosemary. Pour in the vinegar, cover, and shake to combine. Store in the fridge for 4 days, shaking a few times. Strain into a clean jar and discard solids. Serve or place in the fridge.
To Make 1 Cocktail
In a cocktail shaker combine the shrub and gin and shake. Pour into a glass filled with ice and top with club soda. Garnish with ginger and rosemary.
Notes
This shrub can be kept in the fridge for 3 months.
Make sure to use champagne vinegar for this recipe and not white-distilled.