Muddle the mint leaves, blueberries, sugar and lime juice in a mortar and pestle (or use the back of a spoon and a small bowl). Add to shaker along with rum and ice cubes. Shake moderately (not too vigorously) and divide between two lowball glasses filled half with ice.
Top with sparkling water. Garnish with extra mint leaves and blueberries, if desired.
Notes
We added only 1/2 teaspoon of sugar for an added touch of sweetness. Add up to 3 teaspoons for a sweeter drink!I'm hoping for a wonderful, balanced and happy week for you all! Enjoy the recipe and thank you for reading.