First, prepare your ingredients and equipment. Make sure to have your cocktail shaker, strainer, and an appropriate glass ready. Also, fill your glass with ice cubes to keep your Whisky Sour cool.
Pour 60 ml of whisky, 30 ml freshly squeezed lemon juice, 22 ml sugar syrup, and half an egg white into the cocktail shaker. The sugar syrup can be made by dissolving sugar in boiling water and letting it cool, or you can easily buy it ready-made.
Add a few ice cubes to the cocktail shaker and close it tightly. Shake vigorously for about 10-15 seconds to mix the ingredients well and cool the drink.
Use the strainer to carefully pour your Whisky Sour into the ice-filled glass. This ensures that any ice pieces or pulp are left behind in the shaker.
Garnish your drink with a lemon slice or a cocktail cherry, placing it carefully on the rim of the glass as a decorative touch.