I was poking around Sunrise Mart when I came across this gelatinous, vacuum-sealed slab, with a sad-looking potato on the package. Although it’s simply called potato jelly on the English language sticker on the back, it’s actually imoyokan, a very popular Japanese sweet made from sweet potatoes. Imoyokan is part of a very old category of jellied Japanese snacks known as yokan, which are usually made with azuki bean paste (or white bean paste) and jelled with agar agar.
Quoth Wikipedia on the subject of yokan:
Originally a Chinese dish made from gelatin from boiled sheep. It was introduced to Japan by Zen Buddhists in the Kamakura and Muromachi periods. As Buddhism forbids killing, agar was used instead. This modified form became the basis of modern yokan.
The imoyokan that I bought lists sweet potato, sugar, white bean paste, wheat flour and glutinous rice–no agar agar, but I guess the glutinous rice could account for the texture. It is really delicious. Once the plastic is off, it looks much more appetizing. The texture is a bit like Turkish delight. It tastes like a less sweet and more dense sweet potato pie filling.
But don’t take it on the plane. Quoth, again, Wikipedia:
Due to its relative heaviness and unfamiliarity with this dessert, it has been mistaken as C-4 or similar plastic explosives during baggage checks.
If you want to try making imoyokan at home, a recipe is here.