Roasted sweet potato is a popular winter street food in East Asia and parts of Southeast Asia.
In China, yellow-fleshed sweet potatoes are roasted in a large iron drum and sold as street food during winter. They are called kÃÂo-báishà(; "roasted sweet potato") in northern China, wui faan syu () in Cantonese-speaking regions, and kÃÂo-dìguà() in Taiwan and Northeast China, as the name of sweet potatoes themselves varies across the sinophone world.
In 2021, Hong Kong chef Lucas Sin went viral for posting about a traditional Chinese method of roasting sweet potatoes, where the potato is first frozen before being roasted until caramelized sugars bleed through the skin.
Sweet potatoes roasted in drum cans, called gun-goguma (), are popular in both North and South Korea. The food is sold from late autumn to winter by vendors wearing ushanka, which is sometimes referred to as "roasted sweet potato vendor hat" or "roasted chestnut vendor hat". Although any type of goguma (sweet potato) can be roasted, softer, moist varieties such as hobak-goguma (pumpkin sweet potato) are preferred over firmer, floury varieties such as bam-goguma ("chestnut sweet potato") for roasting.
In South Korea, roasted sweet potatoes are dried to make gun-goguma-mallaengi () and frozen to make ice-gun-goguma (). Although gun-goguma has traditionally been a winter food, gun-goguma ice cream and gun-goguma smoothies are nowadays enjoyed in summer.
In Japan, a similar street food is called ishi yaki-imo (; "roasted sweet potato in heat stones") and sold from trucks during the winter.
Roasted sweet potato () is a popular winter street food in Hanoi and Northern Vietnam.
In 2010, an emoji was approved for Unicode 6.0 for "roasted sweet potato".