The Karat Cakery food truck (@karatcakery) sells carrot cake, carrot cake cupcakes and ice cream with carrot cake. So if you don't like carrot cake, don't bother! If you do, however, the carrot cake cupcake with pecans is really divine. They put the cream cheese frosting on the cupcake right after you order it.
The truck was at Farragut North yesterday (Wednesday) although I don't know their schedule.