I've always found French petit déjeuner (breakfast) insubstantial, but that wasn't the first thing that came to mind as I scanned the menu on the blackboard. Gone were the tartines and croissants, replaced instead by a list that read like a biology textbook: rognons de veau (calf's kidney), tablier de sapeur (fried, breaded tripe), tête de veau (calf's head). This was mâchon, a long-standing Lyonnais breakfast tradition where no part of the animal goes to waste.