We used Roland brand lemon-and lime-flavored cocktail cherries in this St. Patrick's Day party-ready Irish Whiskey Sour. They're available in most grocery stores and online.
Put egg white in a shaker; shake until frothy, 30 seconds. Fill shaker halfway with ice; add whiskey, superfine sugar, and juices. Shake 30 seconds.
Wet the rims of two short glasses with an orange slice, then dip in sanding sugar. Add ice; pour in drink. Serve, with an orange slice and lemon and lime cherries.