Add the bourbon whiskey, fresh lemon juice, simple syrup, and egg white to the cocktail shaker without ice.
Perform a dry shake by shaking vigorously for about 30 seconds to create a smooth, frothy texture.
Add ice cubes to the shaker and shake again for about 10 seconds to chill the ingredients.
Strain the mixture into a rocks glass or sour glass filled with ice.
Garnish with a maraschino cherry and serve.
Notes
If you’re concerned about using raw egg white, you can use pasteurized egg whites or an egg white substitute, such as aquafaba, for a similar frothy effect.