Piper lolot leaves (la lot in Vietnamese) are used quite a lot in Vietnamese cuisine. These heart-shaped leaves have a mild peppery taste and a very unique smell once cooked.
Lolot leaves are often confused with betel leaves (la trau in Vietnamese) although lolot and betel leaves are totally different. Some other English names for la lot are wild betel leaves, piper sarmentosum and lolot pepper.
You can find piper lolot leaves (la lot) at Vietnamese grocery stores. They are often sold in a bunch with the stalks still attached, but only the leaves are edible.
In Vietnam, the most common way to use piper lolot leaves is to wrap meat rolls. In the North, the rolls are filled with just pork and then fried. We call these pork rolls cha la lot. Cha la lot can be eaten with rice or noodle soups.
In the South, the rolls, which are called bo cuon la lot, contain mainly beef and are grilled. Bo cuon la lot can be served with vermicelli noodles, lettuce, herbs, roasted peanuts and dipping sauce. Outside of Vietnam, this dish is often translated as grilled beef in betel leaves.
Northerners also use la lot as a fresh herb to add to some soup and stew dishes. As far as I know, people in the South don’t use la lot this way.