The bongkong are characterised by dark blue legs and can grow to a sizeable 32 centimetres. Photograph: Bennett Murray/Phnom Penh Post

They go by many names: freshwater lobsters, king prawns, Mekong langoustines. But whatever the confusion over their identity, one thing is clear: we like them. The giant prawns of the Mekong Delta are in vogue, winning the hearts of many in Cambodia and beyond.

As the Cambodian middle and upper classes grow, local freshwater crustaceans are increasingly sought after in Cambodia’s upscale restaurants.

Known to Cambodians as bongkong and to the scientific community as macrobrachium rosenbergii, the giant river prawn lives in the estuaries of the Mekong Delta around Takeo, Prey Veng and southwestern Vietnam. They can grow to a 32 centimetres in length. Because of their enormous size, they are often billed as lobster, though officially classified as a prawn.

At Malis Restaurant, executive chef Luu Meng, who has rubbed shoulders on television with both Gordon Ramsay and Anthony Bourdain, is experimenting with several new dishes, including wok-fried bongkong served with prahok and fresh coconut juice, as well as bongkong marinated with garlic, sweet nutty pandan juice and served with a spicy tamarind sauce.

The flesh itself has a mild shrimpy taste and acts as a sponge for other flavours in the dish. It is much more subtle on the palate than saltwater shellfish and has a firmer texture than most shrimp or lobster.

Meng described bongkong, which begin their lives in the Mekong’s mouth and work their way up the Mekong and Tonle Sap rivers, as a worthwhile alternative to their sea-dwelling lobster brethren.

“The bongkong is more sweet and fresh. And the brain is very creamy. The lobster, when it’s prepared live and is nice tasting, has a more salty and mineral taste.”

The best bongkong, Meng said, are fished from the wild, as the farm-raised kind do not have the same muscles.

Bongkong, or Mekong langoustines, have become popular. Photograph: Bennett Murray/Phnom Penh Post

“The wild one is always better tasting . . . it is more natural. It works harder to get food. Sometimes farms don’t have the correct feeding methods.”

At the Intercontinental Hotel, the prawn is served poached with a potato cake and caramelised lemon, while at Topaz it is grilled with cheese.

“It is one of our most popular dishes,” said Marcus Gonzagas, manager of the hotel’s Regency Café.

 For fishermen, the Cambodian bongkong trade is lucrative. They caught more than 50 tonnes last year. The amount of bongkong in the wild, which is starting to increase after dwindling for the past decade, reflects its increased popularity.

“There is some illegal fishing, using traps,” said General Director of the Fisheries Administration Nao Thuok, who added that the ever increasing price of bongkong tempts poor villagers to break the law.

 But with costs as high as $48 a kilo, some restaurant owners do not believe it justifies the expense.

 “It’s very nice, but we do not use it because it is so expensive,” said Van’s Restaurant chef Nicolas Malherbe.

 The prawn’s allure stretches overseas. Robert Vifian, chef at Vietnamese Tan Dinh restaurant in Paris, said he fondly remembers the giant prawn from his youth in Vietnam, and continues to use them occasionally for both the meat and roe.

 “It is sweet, firm, fleshy, and aromatically between sea and [other] river prawns,” said Vifian, who uses frozen prawns imported from Vietnam. Called saphira in France due to their dark blue legs, Vifian said he doesn’t serve them often because customers would rather pay the same price for actual lobsters.

Growing up in southern Vietnam, Vifian said, the prawns were an expensive treat that were a rare source of indulgence. Now, they’re gracing the plates of gourmands around the region.