In the northwestern Chinese city of Lanzhou, where the Yellow River cuts through the landscape and the air carries the scent of hand-pulled noodles and roasting lamb, there is a humble dessert that has been quietly warming the hearts of locals for over three centuries. Its name is hui dou zi (灰豆子) – literally “grey peas” – a name that doesn’t do justice to the rich, dark, sweet, and savoury porridge that lies beneath. Often overshadowed by the city’s famous beef noodles, this unassuming bowl of goodness is one of Lanzhou’s best-kept culinary secrets.
What’s in a Name?
The name hui dou zi is wonderfully literal – and a little misleading. The “hui” (灰) doesn’t actually refer to the colour of the peas, but to the key ingredient that makes this dish unique: peng hui (蓬灰), a traditional edible alkali made from burning a local desert plant called peng cao (蓬草) that grows in the Gobi Desert. The “dou” (豆) refers to the mottled grey-green peas – known locally as ma se wan dou (麻色豌豆) – that give the dish its speckled appearance. Put them together, and you get a dish that is, quite simply, a pea soup made with a special plant-based alkali.
A History Steeped in the Streets
The story of hui dou zi begins in the early Qing dynasty, over 300 years ago. According to historical records, the dish was first created by a Hui Muslim family in the Nan Tan area of Lanzhou (now known as Huzhu Alley) during the late Qing dynasty. But unlike many famous dishes with named inventors, hui dou zi is the product of pure folk wisdom. There is no single creator – just generations of street vendors who perfected the recipe through trial and error.
For centuries, these vendors would carry their wares through the streets of Lanzhou on carrying poles, with loads weighing as much as 300 jin (about 150 kilograms). They would set up their stalls with a single coal stove and a rough clay pot, where the dark purple porridge would bubble away for hours. As one local recalled: “In the past, after watching a play or playing cards, the ladies would call for a late-night snack – and it would always be the hui dou zi from the street corner stall, lit by a dim kerosene lamp”.
The Secret of the “Grey”
The magic of hui dou zi lies in the peng hui. This traditional alkali, made by burning the desert plant peng cao and collecting the ash, is what gives the dish its distinctive character. When added to the pot, the peng hui works its slow magic on the tough, hardy peas, breaking them down until they become soft, creamy, and almost custard-like without completely dissolving into a paste. The result is a texture that locals describe as mian sha (绵沙) – velvety and slightly grainy, with each pea retaining just a hint of its original shape.
The peng hui also gives the soup a subtle, almost savoury depth – a flavour that is neither sweet nor bitter, but something in between. As one food writer put it: “It’s a taste that lingers, a whisper of the Gobi Desert in every spoonful”.
The Art of Making Hui Dou Zi
Making authentic hui dou zi is a labour of love that demands patience and skill. The process begins the night before, when the mottled grey-green peas are carefully picked over and soaked in water for at least 12 hours until they swell and soften. The next morning, the peas are drained and stir-fried in a dry iron wok until they release their nutty aroma. They are then transferred to a clay pot, covered with water, and brought to a boil.
This is where the peng hui comes in. A small amount is added to the pot, and the mixture is left to simmer over a low flame for several hours. As the water reduces, more boiling water is added – sometimes two or three times – until the peas have broken down into a thick, creamy porridge. Finally, pitted red dates and rock sugar are stirred in, and the pot is left to simmer for another half-hour until the dates have released their sweetness into the soup.
The finished dish is a deep, glossy coffee-brown or dark purple, with the red dates floating like jewels on the surface. The texture is thick and creamy, but not heavy – the peas are soft without being mushy, and the soup is rich without being cloying.
A Dish for All Seasons
One of the most remarkable things about hui dou zi is its versatility. In the sweltering heat of a Lanzhou summer, it is served chilled – a cooling, refreshing treat that locals swear by as a remedy for the heat. In the bitter cold of winter, it is served piping hot, straight from the clay pot, warming the body from the inside out.
The dish is also valued for its health benefits. The peas are naturally cooling, while the red dates are warming – together, they create a balanced dish that is said to nourish the spleen, aid digestion, and boost vitality. It is rich in vitamins B and C, dietary fibre, and minerals, making it a nutritious choice for young and old alike.
The “King of Grey Peas”
While hui dou zi has no single inventor, it does have a modern champion. In 1962, a young man named Du Weicheng (杜维成) apprenticed under a Hui Muslim master named Ma You, learning the traditional art of making hui dou zi. For decades, Du carried on the tradition, first as a street vendor with a carrying pole, then from a fixed stall. His dedication paid off: in 1989, he was officially recognised by the Gansu Provincial Department of Commerce as the “King of Grey Peas of Jincheng” (金城灰豆王).
Today, Du’s shop, Du Ji Sweet Foods (杜记甜食), located at 72 Dazhong Xiang in Lanzhou’s Chengguan District (兰州市城关区张掖路大众巷72号), is a certified “China Time-Honoured Brand” and a must-visit destination for anyone seeking an authentic taste of old Lanzhou. The shop still uses the traditional slow-cooking method, with each batch of hui dou zi simmered for six hours to achieve the perfect texture.
Apart from grey bean dessert (hui dou zi), the restaurant also serves Lanzhou‑style snacks such as sweet fermented barley (甜胚子, Tianpei Zi) and cold wheat noodles (凉皮, Liangpi).
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