Like other reviewers I could not find this place. Yet on the last day of my stay in Fukuoka I found their outlet. It is located on the base floor of Hakata station (the main station of Fukuoka) near a bunch of shops that sell so-called "Bento Boxes".
Bento boxes are traditional Japanese lunch boxes with little compartments for each part of the meal. Evah offers an assortment of lunch boxes and sweets on the station. Based on the advice of the sales girl I choose the one with the most variety, so I could really sample everything Evah can do.
Based on this rather cheap and cold lunch box I would definitely search harder for the real Evah restaurant next time I visit Fukuoka. It is much taster than a basic bento box and it simply feels healthier. If their outlet offers this quality, the actual restaurant should be excellent!Pros: low price, high quality, healhty
Cons: still haven't found the real place