In a plastic container with a well fitting lid stir together all ingredients except club soda. Cover and freeze for at least 24 hours, stirring once or twice.
Stir slush to break apart. Scoop 1/2 cup of slush into glasses and top with club soda to taste, approximately 1/4 cup. Stir slightly to incorporate the club soda and enjoy!
Recipe Notes
To make simple syrup, combine 1 cup sugar and 1 cup water in a small sauce pan. Heat until sugar has completely dissolved. Cool to room temperature.
Slush will last a month in the freezer in a covered container.