Reewee said:
Nickname: 豆酥_北海道で熊狩りやりたいな
http://www.pixiv.net/member.php?id=3402936

I got Amatsukiryoyu from the website link
Theres also Dou_Su which is signed on some pieces.

dou_su is correct.

http://en.wiktionary.org/wiki/豆酥