Every food-loving visitor to Huế seems to come home with the same souvenir: a jar of mắm tôm chua, the city's famous fermented sour shrimp. It's tangy, spicy, a little funky and a striking red-orange colour — and it just earned international bragging rights, with Taste Atlas naming it one of the 54 best side dishes in Southeast Asian cuisine last month.

Though it's now sold everywhere in Vietnam — traditional markets, supermarkets, even mini marts — the dish has deep Huế roots. Local tradition traces it back to Gò Công in the former Tiền Giang province, from where Queen Từ Dũ introduced it to the imperial court in the early 19th century. Emperors Thiệu Trị and Tự Đức were fans, and the recipe was refined into a so-called 'royal dipping sauce' served at banquets. From there it leaked out through court staff and eventually became an everyday staple for ordinary families.

The making of it is a patient process. Fresh shrimp are rinsed, de-headed, soaked in rice alcohol, then mixed with galangal, bamboo shoots, garlic, red chillies, fish sauce and sticky rice. The lot goes into a ceramic jar to ferment for seven to 10 days, after which it's often enriched with honey and more galangal and packed into glass jars. The result keeps the shrimp looking surprisingly fresh and delivers a layered bite: sweet shrimp, chilli heat, aromatic galangal and garlic, and chew from the glutinous rice.

Traditionally it accompanies thinly sliced boiled pork, sautéed bean sprouts, local figs or boiled water spinach — the sour, salty, sweet and spicy balance cutting richly through it all. One local writer's take: steamed rice, freshly boiled pork, a spoonful of the shrimp and pickled cucumber makes a perfect meal. A more DIY version wraps the shrimp in rice paper with fresh herbs, green banana, starfruit and pickled vegetables, dunked in sweet-and-sour fish sauce.

For travellers, this is the ideal edible souvenir: compact, long-lasting and available at Huế's Đông Ba Market, where you can taste before you buy. It also works as a gateway into Huế's broader food scene, one of Vietnam's most distinctive thanks to its imperial heritage — think bún bò Huế, banh khoai and royal-style banquets. Even if you never make it to central Vietnam, jars are sold nationwide, so a taste is easy to add to any Vietnam itinerary.