"I forget already what they told me it was," said one cake customer.
It is a whoopie pie.
"I come from the west coast so I don't really know whoopie pies that well."
"It's chocolate cake with seven minute frosting in the middle,' says Michael Lebowitz, a cashier at Something Sweet. "Kinda tastes like marshmallow."
Beloved and claimed as local inventions by Maine and Pennsylvania, they're increasingly making their way onto bakery shelves across the country - and into their local lexicon, reports CBS News correspondent Michelle Miller.
You know the story behind the name? Apparently Amish farmers, their wives would put them in their lunch pail and when they found them, they said whoopie. There you go!
San Francisco authors Sarah Billingsley and Amy Treadwell grew up with the treats and devoted an entire cookbook to them.
"Certainly when we talk about a whoopie pie, not everyone knows what that is. But as soon as we describe it they go 'oh, it's like a moon pie, or oh, it's like an oreo,'" Billingsley says.
"A whoopie pie is so much less intimidating than putting a big cake together," Treadwell adds.
And they say there's much more to it them than just chocolate and vanilla.
"We have wildly deviated from tradition, we freely admit," Billingsley says. "We have flavors, we have savory whoopie pies, like a jalapeño cornbread with a goat cheese filling."
No sign of goat cheese, but there are more than 100 flavors at the annual whoopie pie festival in Lancaster, Pennsylvania, in the heart of Amish country.
They're used for "breakfast, dinner and supper, and a midnight snack," says one local.
Here they put pies on a pedestal - with whoopie pie checkers, a table to make your own and the world's largest whoopie pie, which gets the celebrity treatment.
But true celebrities are known countrywide.
"We've seen them in San Francisco, I've seen them in San Diego, I know that they're big in L.A. right now. And then New York. But yeah, you're not seeing in Iowa," Billingsley says.
At least, not yet.