What is an egg cream and why is it so Jewish?

An egg cream was my father's kitchen claim to fame. He assembled them with great flourish - Fox's U-Bet chocolate syrup, cold milk from a glass bottle, and a long, hard shpritz of seltzer, followed by a vigorous stir. Even today, when I drink or think of it, it takes me back to my family's Brooklyn roots, and him.

To my surprise, I have discovered that I am not alone in my nostalgic connection to this fancy-named but pedestrian drink. According to Pete Freeman, co-owner, cofounder and chief soda jerk at Brooklyn Farmacy and Soda Fountain, nostalgia is at least half of the egg cream's appeal. T...