I probably should've read up on this before I went shopping, but nevertheless I think I got a good butter for the Breton butter cake.The label made me curious: Pamplie buerre de baratte A.O.C. Charentes-Poitou Extra fin
By way of eGullet, I found this discussion on butter (Pamplie is mentioned) which in turn led me to Ptipois' blog for a fascinating post + pictures on the making of Saint-Coal butter.
There's so much out there I don't know anything about.
It makes me glad.
