Strawberry-Basil Shrub Cocktail

To prepare shrub: Pour boiling water over a quart jar and lid to sterilize. Let stand for 10 minutes, then empty and let cool.

Add strawberries and sugar to the jar; use a wooden spoon to mash the berries until chunky. Cover and let stand at room temperature for 24 hours.

Add vinegar and basil sprig. Cover and gently shake until the sugar has dissolved. Refrigerate for 1 week.

Strain the mixture through a fine-mesh sieve, pressing on the solids with a wooden spoon to extract the liquid. Wash and resterilize the jar and lid. Return the shrub to the jar.

To prepare cocktail: Fill a highball glass with ice. Add gin, liqueur, bitters and 1 oz. shrub; stir to combine. Top with a splash of club soda (or seltzer). Garnish with basil, if desired.