The first time the South Korean factory owner watched his North Korean employees nibble on a Choco Pie, they appeared shocked - even overwhelmed.

He summed up their reaction to the South Korean snack in one word: "Ecstasy."

Much like what Twinkies are to Americans, South Korea's Choco Pies - two disc-shaped, chocolate-covered cakes, sandwiching a rubbery layer of marshmallow cream - are ubiquitous, cost less than 50 cents and are full of empty calories.

But on the other side of the Korean border, the snacks are viewed as exotic, highly prized treats, selling on North Korea's black markets for as much as $10, according to analysts. Their rising popularity in the north reveals an unexpected common ground between the two Koreas, despite their fractious relationship - a shared sweet tooth.

This month, an art exhibition called "The Choco Pie-ization of North Korea" opened in New York, exploring the symbolism of the treat. The high value in North Korea of the Choco Pie, something considered so widespread and mundane in South Korea, is "a sad tragic story," said the artist, Jin Jo Chae.

Chae smeared melted chocolate across the North Korean newspaper Rodung Sinmun, staining the state-run propaganda with something sweet. She used the chocolate to make a symbol of Choco Pie, written in the lettering style of Coca Cola. Her exhibit, displayed at Julie Meneret Contemporary Art gallery, also contains piles of Choco Pies as well as a gold-plated one.

"Through this Choco Pie, I found the potential from chocolate as an object that changes a society," Chae said.

The Choco Pie represents something more than just a treat.

Read - How Choco Pie infiltrated North Korea's sweet tooth