Sweet potato snack?
 

I'm really annoyed at myself because I'm sure I've asked this before, but I ate this snack in Japan a couple of times and I can't for the life of me remember the name or find it online. It was a block (fairly sizeable, meant for sharing) of sweet potato an that had been dipped in a thin batter and then each side had been cooked on a teppan style griddle. Mostly it seemed to be sold from tiny street-side shops.

From your description, I would say it was きんつば or いもきんつば.

EDIT: Adding a pic of what I'm talking about.

Yes, thats it! いつもどうもありがとうSMさん

I love sweet potatoes. I am curious though is it a piece of sweet potatoe or a dough made of sweet potatoe that is battered and fried.

It's usually made with 90% sweet potato with sugar and agar added. Though I'm not providing a translation, here's how it's made. You will get a good idea just by looking at the photos.

http://www.tsuji.ac.jp/hp/dango/imok.../an/recipe.htm

For the batter:
http://www.tsuji.ac.jp/hp/dango/imok...iji/recipe.htm