Add limoncello, lemon juice, and egg white to an empty cocktail shaker.
Shake, then add ice to the shaker and shake again until well chilled.
Strain into a cocktail glass and garnish with a lemon wheel.
Notes
Pro tip –
Dry shake your cocktails with egg whites. When making cocktails that include egg whites, always shake everything in the cocktail shaker without ice first. Then add ice, and shake again until well chilled.
The ice-less first shake is called a dry shake, which results in a fluffier egg foam on top when it is poured into the cocktail glass.