The "Old-lady sour sausage" stall, run by its elderly white-haired owner, has been serving customers for the past 30 years.

Situated at the corner of Quang Trung Street, near Tam Bac Market in Hong Bang District, the eatery serves only one dish, crunchy and glutinous sour sausages dipped in vinegarish sauce for VND20,000 ($0.86) a pop.

To create the dish, minced pork and finely diced pork skin are wrapped in banana leaves, which carry beneficial yeasts and microbial agents, and paper wraps for slight fermentation.

The process affords a signature fragrant sourness to the sausages, considered a delicacy in northern and central Vietnam.

Sour sausages in Hai Phong, as well as other northern localities, taste less sweet than their central counterparts.

What makes the stall extra special is its signature vinegarish sauce, hand-made using fruits. The sauce has a slight, delicate sourness, which blends finely with the sausages.

Customers often add fresh herbs like apricot and Ming aralia leaves to the dish for an extra kick.

The stall opens from 9 a.m. to 6 p.m. daily, with a customer peak in the afternoon. Takeaways are also available if you buy at least five pieces.