1 1/2 OZ
Key lime juice
Key limes & thyme for garnish
Combine sugar and water in saucepan. Cook, stirring frequently until the sugar dissolves and the liquid is clear. Transfer to a jar and chill overnight.
Combine vodka, lime juice, syrup, egg white, and bitters in a shaker, and shake vigorously 15 seconds until frothy. Add the ice and shake again until very cold.
Strain the cocktail into a chilled coupe glass. Top with lime slices soaked in thyme syrup and thyme sprigs. Serve immediately.