Add cucumber slices to the shaker and muddle gently to release the juice.
Pour in vodka, lime juice, and simple syrup.
Fill the shaker with ice and shake for 15 seconds.
Fill a Collins glass with fresh ice.
Double strain the mixture into the glass.
Top with club soda and stir gently.
Garnish with a cucumber slice and mint sprig.
Notes
Store extra cucumber slices in an airtight container for up to 3 days.Make simple syrup by mixing equal parts sugar and water in a pot. Heat until sugar dissolves, then cool before using.For best results, use fresh cucumbers and chill the vodka beforehand.The drink can be made without alcohol by replacing vodka with extra club soda.