Nuclear Holocaust

Chill a coupe or sour glass by filling it with ice water and setting it aside while you prepare the cocktail.

Measure and add the base spirit, fresh citrus juice, and sweetener into a cocktail shaker.

If using egg white or aquafaba for a classic sour foam, add it to the shaker at this stage.

Perform a dry shake without ice for approximately 15 seconds to emulsify the egg white and build a frothy texture.

Add a generous handful of ice to the shaker and shake vigorously for 12 to 15 seconds until the shaker is well chilled and frosted on the outside.

Discard the ice water from the chilled glass and fine-strain the cocktail through a Hawthorne strainer and a mesh strainer into the prepared glass.

Allow the foam to settle and rise naturally to the top of the drink for 20 to 30 seconds before garnishing.

Garnish with a citrus wheel, twist, or a few drops of bitters floated on the foam, and serve immediately.