Use fresh sweet basil if you can find it for that strong hint of clove it carries. Honey is an option, but if you ask me—and I know you didn’t—pure cane sugar is the best sweetener for citrus because it does not blunt the fruit’s bite nor muddle the liquid. Combine a fistful of rinsed basil—leaves, stems and blossoms, whatever you gather with blithe abandon—with about a quarter cup sugar and crush with a wooden spoon. (If you happen to have a mortar handy, of course that is what you should use instead.) Add basil and sugar along with a half cup of freshly-squeezed lemon juice to a quart of water. Stir until sugar is dissolved, strain and add more sugar to taste. Chill and serve over ice.