Simmer the water with the basil and lime zest for 10 minutes. Let cool and add sugar and lime juice, stirring until fully dissolved. Strain to remove basil and lime zest.
Add 1 ounce of the Basil-Lime Syrup to a glass; fill to top with sparkling water or club soda and ice. Garnish with lime slice and basil.
Notes
Recipe by Robe Pate. Photo by Melissa Skorpil. Reprinted courtesy of Texas Department of Transportation.