As I'd expect of you, you're so knowledgable, Hibiki!Huuuunh?!I have to go and tell Ikazuchi and the others, too!* It's a lieAkatsuki, these sweets are called "Siberia" and are a specialty of Russia.
The type of Siberia in question are sponge cakes made with bean paste filling. They're Japanese. Note that a "Siberian" cookie also exists, and is actually Russian, but the comments on Pixiv indicate that's not what they're talking about.
