Amaretto Sour (Jeffrey Morgenthaler)

Combine the amaretto, cask-proof whiskey, lemon juice, simple syrup, and optionally, the egg white in a cocktail shaker.

Dry shake vigorously without ice or use an immersion blender to achieve a frothy texture.

Add cracked ice to the shaker and shake well again.

Strain the mixture over fresh ice in an old fashioned glass.

Garnish with a twist of lemon peel and a couple of brandied cherries.