Cue the onigirazu. A layer of rice and whatever pleases the soul are wrapped in seaweed into a flat square and sliced in half. Popular fillings include the aforementioned tonkatsu, ham, egg and cheese, tuna salad, caprese salads and more.
According to the Boston Globe, the origin of the rice ball sandwich can be traced back to a manga (Japanese comic) series from the mid-1980s called Cooking Papa.
(FoodRepublic.com)
