How to Make It
In a rocks glass, muddle the lemon zest with the simple syrup, Campari, grapefruit bitters and sea salt. Add the gin and a few ice cubes and stir until well chilled. Top with more ice and serve right away.
To make Demerara simple syrup, in a small saucepan, dissolve 1/4 cup Demerara sugar (a coarse, raw cane sugar) in 1/4 cup water over moderate heat.