Fermented butter is popping up here and there in Tokyo, even at 7-11 convenience stores in these simple fermented butter rolls. You know when a new food trend has become mainstream when it makes it to your local 24-hour combini.
A chef's guide to the best food in Tokyo. My book, Food Sake Tokyo, is part of the Terroir Guides published by The Little Bookroom. Updates to the book are under "updates". My other blog is on cooking Japanese food at home: http://tokyostation-yukari.blogspot.com/. I am represented by Lisa Ekus. lisaekus.com