WATCH: French-US TikToker Amanda Rollins deep in jam over 'buttered sandwich' discovery

A TikTok video showing Amanda Rollins, a US citizen making sandwiches in Paris, France, was published earlier this month with the explanation that the French do something "very weird" that her fans would "find strange."

“What they do, it’s like a classic sandwich, is ham, cheese and … butter. Literally, just swab it on. No mayonnaise. No mustard. Just butter,” Amanda Rollins explained.

“And no, listen, I know you might be thinking that sounds gross but it’s actually so good.”

Foreign viewers were perplexed by the video; Europeans and Australians confirmed that this was "very normal" and not simply a French phenomenon.

The buttered sandwich was tried over the weekend by American lifestyle media Pure Wow.

“Anyone outside of the US would probably agree that butter on a sandwich is totally normal but for many, this is a brand new food hack that they’re just discovering for the first time,” the reviewer said.

“Now this concept is totally new for me and I’ve got to say, I like it. It provides flavor and moisture to your sandwich but it doesn’t make your bread soggy like mayo can.”

“WHAT IS GOING ON IS THIS A PRANK,” commented one TikTok user, gaining more than 23,000 likes in support.

“I am completely confused … why have Americans only just discovered THE MAIN USE OF BUTTER,” another comment said, which had almost 40,000 likes.

Many in disbelief at butter on bread being labeled a “new food hack” thought the review was satire, the NewYork Post reported.

Abbie Chatfield, an Australian media personality, captured a response video of herself acting bewildered and shocked. In just 17 hours, the video had received 3.4 million views.

“Americans be broken on so many levels, this is the kettle thing all over again,” commented one person, referencing the time the internet ruthlessly mocked the US for “discovering” electric kettles last year.

The New York Times published an article with the headline: “A swift and easy way to heat water without using a stove”. It shared a list of the publication’s top product picks and urged readers to “consider the electric kettle”.

Many Australians were curious about what else Americans used butter for outside bread when the issue of buttered sandwiches came up.

“Americans use butter all the time, but we don’t usually put it on a cold sandwich,” one said.

Another clarified it varied depending on location: “I’m from the dead center of the US and have never put mayo on a sandwich, ALWAYS use butter.”