January 24, 2019 (Reuters) - One of India's most well-known meals outside of the country is butter chicken, which is both tasty and, it seems, controversial, with two Indian restaurant groups battling it out in court over who invented it.

The family behind the renowned Delhi restaurant chain Moti Mahal, which has hosted visitors including late US President Richard Nixon and India's first prime minister Jawaharlal Nehru, filed the complaint, which has gained significant attention in India.

The curry is said to have been invented in the 1930s by Kundan Lal Gujral, the restaurant's founder, when it initially opened in Peshawar before moving to Delhi. It has filed a 2,752-page lawsuit against rival business Daryaganj, alleging that it made up a story to claim that it invented both the dish and dal makhani, a well-known lentil dish that is also topped with a lot of butter and cream.

In addition to demanding $240,000 in damages, the Gujral family claims that Daryaganj has imitated "the look and feel" of Moti Mahal's eateries as well as the website's design.

"A person's legacy cannot be taken away... The dish was created during our grandfather's time in Pakistan, according to Moti Mahal's managing director, Monish Gujral.

The relatively new restaurant Daryaganj (opened in 2019) contends that the dish originated in Delhi, where its late family member Kundan Lal Jaggi had collaborated with Gujral to create the establishment in 1947. It contends that this gives it the right to claim credit for creating the dish as well.

To support its claim, Daryaganj provided Reuters with a handwritten, fading partnership certificate that was filed in 1949.

The controversy has drawn national attention, with social media debates and features on the dish's history airing on Indian TV networks.

It's a peculiar and unusual case. It's actually unclear who invented the first butter chicken meal. The court would have to rely on circumstantial evidence and will have significant challenges," said Ameet Datta, an intellectual property attorney of Saikrishna & Associates in India.

According to Datta, testimonials from consumers who can connect a brand to a meal they ate decades ago may be crucial evidence.

This recipe, which consists of tandoor-cooked chicken chunks blended with tomato gravy and dollops of cream and butter, came in at number 43 on TasteAtlas' ranking of the "best dishes" in the world based on ratings from around 400,000 users. After butter garlic naan bread, it was chosen as the second-best Indian dish. Frequently, the two are coupled together.

The Delhi High Court heard the matter for the first time last week, and a new hearing is planned for May.