Invented in New Orleans in 1888, this concoction needs vigorous shaking to produce its distinctive frothy cap.
In a cocktail shaker filled with ice, combine gin, lime juice, lemon juice, orangeflower water, sugar, egg white, and light cream (or half-and-half). Shake vigorously, and pour into a cocktail glass. Top drink with seltzer, and garnish with ground cinnamon, if desired; serve immediately.
Raw eggs should not be used in food prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.