1/4cupsugarreduce to 2 tablespoons for a less sweet shrub
1/2cupbalsamic vinegaryou can also try a mix of balsamic and a lighter vinegar, like apple cider or champagne
For the cocktails:
Combine the strawberries and sugar; mash with a fork until well-combined. Cover and refrigerate overnight. Once a syrupy liquid has accumulated, strain through a fine mesh sieve (reserve the solids to use over yogurt or on toast). Stir the vinegar into the syrup and refrigerate for several hours (ideally a day or more), stirring occasionally to help dissolve the sugar.
To assemble the shrub cocktails, muddle a few leaves of basil in the bottom of a glass, if using. Remove basil leaves and add 1-2 oz gin, 1 oz shrub syrup, 1/2 cup sparkling water, a squeeze of lime and stir. Adjust components to taste.