In Japan, an all-you-can-eat buffet is also called a "viking" (baikingu). It may sound weird but it's true.
According to the japanese wikipedia, the manager of the first buffet restaurant in Japan (at the Imperial Hotel of Tokyo) travelled to Denmark and took inspiration from the danish smörgåsbord. But the word smörgåsbord was too difficult to pronounce in japanese. Back then, the 1958 movie "The Vikings" was popular. There is a scene in the movie where vikings are eating heartily so they decided to name it "Viking Restaurant". And from there, the word "viking" became associated with "buffet".
In this Biyori chapter, the members of Kiyosumi go to a cake viking. I could have translated it as "cake buffet" but then the second strip in page 2 would make no sense, so I left it as cake viking. I hope you like it.