Following heavy rains, the inhabitants of Ninh Binh look for a unique culinary treasure known as “dun da,” or rock moss, which emerges from the mountain rocks. This moss flourishes in the damp conditions on limestone formations and has been a longstanding local delicacy.

Dun da, characterized by its jelly-like texture and greenish translucence, appears only after summer rains, clinging to the wet crevices of the region’s majestic limestone hills. Traditionally, during times of scarcity, locals would brave the mountains to gather this moss for additional nourishment. Nowadays, it is highly coveted as a delicacy.

Resident Yen Nhi comments on the challenges of harvesting rock moss, emphasizing the risk involved due to its steep mountain habitats and the short window for collection after rainfall. “It needs to be picked immediately following the rain,” she notes, “as it quickly dries out and becomes unusable.”

Preparing dun da is an intricate task. Nhi explains that the moss, akin to jelly and often coated in debris, must be cleaned thoroughly. This involves soaking it in rice water and rinsing several times to ensure all dirt is removed before cooking. The simplest method of preparation is boiling, usually served with a peanut salt dip.

“By boiling dun and pairing it with peanut salt, you maintain its natural flavor, making it a quick and simple dish,” Nhi mentions, highlighting the traditional cooking style of Ninh Binh.

While boiled dun is the classic way to enjoy it, creative recipes have emerged, including stir-fried dun, salad with shrimp and pork, and a pickled variant. A particularly cherished dish is the crab soup featuring dun, which many visitors seek out. The moss is briefly blanched and combined with a savory crab broth made from fresh crabs, tomatoes, meatballs, and tofu, resulting in a deliciously tangy and refreshing meal.

The special characteristics of rock moss – its seasonality and invigorating flavor – turn it into a sought-after delicacy from Ninh Binh’s limestone regions. Outside its peak season, from June to August, finding fresh dun can be challenging, even for those willing to pay well, with prices at around 20,000–30,000 VND per kilogram at peak times and 35,000–40,000 VND off-season.

To cater to year-round demand, locals also produce dried dun. This process is labor-intensive, requiring 3 to 4 kilograms of fresh moss to create just one kilogram of the dried version, which costs between 90,000–100,000 VND, depending on the season and market.

Thanks to its light and refreshing nature, rock moss has become an ideal summer dish, enchanting both locals and tourists alike with the authentic flavors of Ninh Binh’s rugged landscape.