Roasted sweet potato

Regions

Across China, winter street vendors roast yellow-fleshed sweet potatoes in large iron drums. The name varies by region: kǎo-báishǔ in the north, wui faan syu in Cantonese areas, and kǎo-dìguā in Taiwan and Northeast China. In 2021, Hong Kong chef Lucas Sin gained attention for a traditional method that freezes the potato before roasting until caramelized sugars seep through the skin. In both North and South Korea, drum-roasted sweet potatoes are called gun-goguma, sold from late autumn through winter by vendors in ushanka hats, sometimes known as roasted sweet potato or chestnut vendor hats.

Softer, moist varieties like hobak-goguma are favored over firmer, floury types such as bam-goguma for roasting. South Korea also produces dried gun-goguma-mallaengi and frozen ice-gun-goguma from the roasted potatoes. Though gun-goguma is a winter staple, gun-goguma ice cream and smoothies are now summer treats. Japan offers a similar winter street food called ishi yaki-imo, sold from trucks. In Hanoi and northern Vietnam, roasted sweet potato, or khoai lang nướng, is a popular winter street food.