Add the whiskey, lemon juice, and simple syrup to a cocktail shaker. Fill with a handful of ice and shake until very cold.
Strain the cocktail into a glass (with or without ice) and garnish with the orange slice and cherry on a toothpick.
Whiskey Sour (With Egg White)
Add the whiskey, lemon juice, simple syrup, and egg white to a cocktail shaker without ice. Shake for 15 seconds.
Add ice to the cocktail shaker. Shake again for 30 seconds.
Strain the drink into a glass; the foam will form a layer on the top. Serve with or without ice and garnish with the orange slice and cherry on a toothpick.