2 ounces whiskey/bourbon
3/4 ounce lemon juice, freshly squeezed
1/2 ounce simple syrup
1/2 ounce egg white (optional)
Garnish: Angostura bitters
Add whiskey, lemon juice, simple syrup and egg white, if using, to a shaker & dry-shake for 30 seconds without ice.
Add ice and shake again until well-chilled.
Strain into a glass.
Garnish with 3 or 4 drops of Angostura bitters.