ogawaken raisin wich

hi everyone,

Irecently did the opening of a new bakery in London and  the chef of our deli is a japanese cuisine lover, in one of his trip to japan brought me back those amazing biscuits called ( ogawaken raisin wich) and apparently he's saying that the recipe is kind of secret.i was wondering if anyone has ever herd of this biscuits?.

I know the chef quite well and I think was a kind of a challenge,to see if I could reproduce It would be fantastic if anybody could help!

thankyou so much!!!!!!!!

regards to all

stefano