Place the blueberries, mint leaves, and simple syrup in the bottom of a glass. Gently muddle the blueberries and mint in the simple syrup until the blueberries are crushed and the mint leaves are bruised and starting to break down (they'll get really dark green as they release their oils).
Add the bourbon and then give all of the ingredients a quick stir.
Add enough crushed ice to fill the glass to the rim, and then pour the soda water over the ice. Garnish with a mint sprig and drink immediately.
Blueberry Mint Julep https://oursaltykitchen.com/blueberry-mint-julep/