By Harold McGee
A second kind of preserved egg, little seen in the West, is made by covering gently cracked eggs in a fermenting mass of cooked rice or other grains mixed with salt: in essence a concentrated and salty version of sake or beer. Zaodan mature in four to six months and take on the aromatic, sweet, alcoholic flavor of their surroundings. Both white and yolk coagulate and fall out of the softened shell. Such eggs can be eaten as is or cooked first.
From the book On Food and Cooking (2nd edition) by Harold McGee. © 2004 Harold McGee. By permission of Scribner, a division of Simon & Schuster, Inc.