A Yamagata delicacy.
It's green peas boiled in some kind of sweet flavoring. I had some for the first time today and loved it. The texture is soft and crumbly, like simmered kabocha or daifuku filling, and the flavor has that lovely, mild sweetness of other traditional Japanese treats. I'm not sure you can find fukimame easily outside of Tohoku. If you're ever in Yamagata, you can get some at a shop downtown called Yamada-ya. It's famous for fukimame and sells out every afternoon.