Rognons de Veau à la Moutarde

I was recently in Paris, walking down a narrow street in Saint-Germain-des-Prés with a friend, and as we passed an intersection, she stopped and pointed out a shabby-looking bistro halfway down the block. “That place there,” she said, beginning to breathe heavily, “they have the best rognons in Paris. Soo divine!” She stood there wistfully, as if remembering a former lover, before moving on. I recall thinking, “This is someone who must really love kidneys—to have apparently searched