50 ml bourbon
2 tsp simple syrup (sugar dissolved in equal parts water in a pot)
25 ml lemon juice (just squeezed)
1 large egg white
1 dash of Angostura bitters (3-4 drops)
Fill a cocktail shaker halfway with ice. Add bourbon, egg white, lemon juice and simple syrup and shake vigorously for 20 to 30 seconds. Pour into a cocktail glass, top with bitters and serve.