- In a pot over medium-high heat, bring all the ingredients to a boil, then simmer for 5 minutes. Let cool. Strain through a sieve.
- In a glass, combine the sparkling water and cup (60 ml) of the shrub. Add ice and garnish with the lemon slice and a few frozen cranberries or raspberries.
The shrub will keep for 1 month in an airtight container in the refrigerator.