A friend of mine, who sells books on a number of subjects (including historic food and costume) and trades as Poison Pen Press just sent around e-mail about the following book that is coming out this winter:
Rath, Eric C. and Stephanie Assmann, eds. Japanese Foodways, Past and Present. University of Illinois Press; 1st Edition (Oct. 7, 2010).
This book contains a number of scholarly essays about Japanese food in the late medieval and early modern period. It's a trade paperback, 290 pages, and the list price is $28. Worth considering by historians of medieval food, as well as aficionados of Japanese food.