Add mango juice, salt, basil simple syrup in the bottom of a tumbler and stir. Fill glass with ice and top off with sparkling water. Garnish with basil leave and sliced mango.
To make simple syrup, add 1 cup of sugar and 1 cup of water to a small sauce pan over low heat. Stir with a whisk until sugar dissolves. Add 4-5 leaves of fresh basil and continue to simmer for 5 minutes. Remove basil leaves and store in a sanitized jar. Use as needed for your favorite mocktails!