Rognons or similar
Bourdain and Batali like offal so their restaurants (try Casa Mono). I just checked Ramsey's place at the London, it's a pity he doesn't have deviled kidneys for breakfast . Any restaurant which serves a traditional British mixed grill should have them but I can't think of where at the moment! Another great thing is black pudding, I wonder who has that.
52 Irving Place, New York, NY 10003