Add your amaretto liqueur, bourbon, lemon juice, simple syrup, and egg white (if using) to your cocktail shaker.  If using egg white, put the lid on the cocktail shaker and shake for 15-20 seconds...this is referred to as a dry shake, and helps the egg white foam form.

Add ice to the cocktail shaker, then seal the shaker and shake until the outside of the shaker is frosty, about 15-20 seconds.

Strain into a couple or small rocks glass (I prefer without ice, but it's your choice) and garnish with an Amarena or bourbon cherry.