In a large cocktail shaker, combine 1 large egg white, 1 lemon twist, 1 orange twist, 4 oz. amaretto, and 2 oz. fresh lemon juice.
Seal and shake vigorously without ice for 30 seconds to emulsify egg white.
Unseal shaker, add ice, and shake vigorously again until shaker is well chilled.
Strain into 2 stemmed coupe glasses.
Dot the froth with Angostura bitters using a dropper and garnish each with a cocktail cherry on a pick, if using.
