Step 1: Combine blueberries, rosemary, sugar, and a tablespoon of water in saucepan over low heat. Allow the the blueberries to release their juices - about 5 minutes.

Step 2: Gently crush the blueberries with the back of a spoon, and add 2 cups water to the mixture. Stir to combine and simmer on very low for about 30 minutes. You want the consistency of syrup rather than jam, if the mixture becomes too thick, add more water and reduce heat. 

Step 3: After about 30 minutes, the mixture should resemble syrup. Remove the rosemary sprigs, and place the syrup into a glass jar to cool. 

Step 4: Once cooled, spoon 1 tablespoon of syrup into a champagne glass. Top with sparkling wine or champagne and enjoy! 

Don't forget to garnish your patriotic cocktail with a DIY 4th of July cocktail stirrer!