Treat yourself to a tart, bitter, citrusy sour with this Aperol Sour featuring gin, Aperol, floral bitters, grapefruit and lemon juices, and egg white. It’s a lighter take on my usual whiskey sours, full of tart bitter flavors softened and sweetened with the egg white and the Aperol. For a bigger bitter bite, try Campari instead of Aperol.