Officials in Luxembourg are setting up a warning system to alert authorities, vendors, and innocent bystanders when someone attempts to put ketchup or other unauthorized condiments on their Gromperekichelcher.

The Gromperekichelchen, a fried potato cake that is often served at Christmas markets and other outdoor events, is considered a national treasure and has a special protected status.

The new warning system will be installed nationwide, with sirens located at every outdoor gathering place across the Grand Duchy. Officials are asking residents to intervene if a siren sounds.

"There are only three condiments that you may – legally, ethically, and practically – combine with Gromperekichelcher," said Jempy Elvinger, a fourth-degree Guardian of the Traditions and Keeper of the Eternal Flame of the Order of the Sacred Potato. “Apple sauce, apple purée, and apple mush."

Experts say that every year, hundreds of people, mostly tourists but a few expats, allow their morbid curiosity to control them and, in a fit of obscene indulgence, put something else on their Gromperekichelcher.

"In 2019 we caught a Belgian man eating Gromperekichelcher with a dollop of mayonnaise, but luckily some onlookers tackled him, removed the innocent potato cake of the offending sauce, and send the item to a clinic in Esch for specialised cleaning," Elvinger said.

Other incidents include a Mexican citizen putting chipotle hot sauce on a Gromperekichelcher in 2009 and a Canadian putting something resembling brown gravy on a Gromperekichelcher in 2012.

"Just last year, an Indian citizen placed a Gromperekichelchen in a bowl and totally covered it in tandoori sauce," Elvinger said. "The poor cake had no chance."

"It was found floating in the bowl three days later, uneaten, to no one’s surprise," he continued. "A tragedy. If this new system can save just one Gromperekichelchen from a sad, shameful end, then it will be worth it."