Harvey Randall is a member of the Gates of Heaven Congregation in Schenectady NY who makes this concoction each year for the Jewish Food Festival. He shared his egg recipe with Daniel Berman of Fussy Little Blog. It’s untraditional, but close to what you’d get at a New York lunch counter, and very easy.
1 part chocolate syrup (he specifies Fox’s U-Bet but I’ve used Hershey’s without serious consequences)
4 parts whole milk
8 parts seltzer water
Method: Milk and seltzer should both be chilled. Combine ingredients in a wide-mouth jar with a lid. Shake vigorously for 30 seconds until very fizzy. Pour into serving glasses and serve.