This Rich Dip Highlights Century Eggs’ Complex Flavors

Despite their name, century eggs (pídàn, 皮蛋) are not actually preserved for a hundred years—we can thank Western sensationalization for the misconception that they are extremely old and funky. In reality, it takes only a few short weeks to transform eggs (chicken, duck, quail, you name it) into this delicacy. Once you have preserved your eggs, you can use them in a variety of ways, mixing them into congee, slicing them on top of tofu or eating them on their own with a light drizzle of chili oil. At my weekly supperclubs in Brooklyn—where I serve some by-the-book Sichuanese dishes along with some newer takes on dishes from neighboring provinces—I’ve been making a dish that shows off this ingredient’s unique flavors: eggplant-century egg dip (léijiāo pídàn qíezi, 擂椒皮蛋茄子).

Century eggs have ancient origins. Legend says that around 600 years ago in Hunan province, during the Ming Dynasty, a farmer discovered some duck eggs in his backyard, soaked in a pool of water containing leftover slaked lime from a construction job. Over the course of two months, the alkaline solution had transformed the egg into a dark, translucent, jelly-like consistency with a jammy black yolk. To his surprise, not only were the eggs edible, they were also savory, umami and complex. 

What originated as a chance occurrence evolved into an intentional preservation method. Today, cooks all over China preserve eggs using this method so that they can store them for up to 18 months—and because the eggs are prized for their unique flavor. When I visited Hongqi village in the Shengzhong Lake region of Sichuan this past summer, the local pidan master explained that the name comes from 皮 (pí, coating/covering) and 蛋 (dàn, egg), referring to the layer of coating that goes on the outside of the egg during preservation in the modern preservation process.

Today’s method has evolved a bit from the original, accidental process: Each egg is coated with a thick alkaline mixture made up of clay, wood ash and lime, and the coated eggs are then rolled in a layer of dried rice husks or hay to prevent them from sticking together, and left in a dry, cool place for three weeks. The porous nature of egg shells allows the alkaline outer coating to raise the pH of the egg whites and alter their chemistry, denaturing the proteins, which gives them a jelly-like texture and prevents spoilage. 

Once the process is complete, the century eggs can be stored at room temperature, though I always refrigerate mine to be safe. In wet markets in China, they are often sold with their coatings still in place; in Asian markets in the US, you’ll find them vacuum sealed and packaged in tidy boxes. The result is an egg that is savory and pungent—comparable to a strong aged cheese with hints of sulfur and minerality. The yolk is creamy, jammy and smooth, while the egg white is gelatinous and slightly firm. You can eat century eggs raw or incorporate them into other dishes, like leijiao pidan qiezi.

Pidan is not to be confused with another common preserved egg, 咸鸭蛋 (xián yādàn), or salted duck egg. Both involve submerging eggs in salty mixtures, and both are sometimes eaten with congee, but the similarities end there. The main difference lies in the mixture the eggs are preserved in: pidan uses an alkaline mixture, while xian yadan is preserved with salt alone. Xian yadan also stays white and has a much less funky flavor.

Here in the States, non-Chinese cooks and eaters have long considered century eggs a type of  “untouchable” food only fit for food challenges. (They most famously appeared on the television show Fear Factor.) But perhaps this is because Westerners are unaware of how to prepare this prized ingredient. The most common use of pidan in New York Chinatown’s Cantonese restaurants is in 皮蛋瘦肉粥 (pídàn shòuròu zhōu), congee with century egg and slivers of lean pork. In this dish, the warm and slippery pieces of pidan (usually made from duck eggs) are gently folded into the silky porridge, adding a slight funk and some richness to the gently seasoned rice. This use of the century egg as a subtle addition to a lightly flavored dish serves as a great gateway into the world of preserved eggs. 

In contrast, in Sichuan and Hunan provinces, pidan is often served as the star of a dish and is commonly eaten cold and heavily spiced, dressed in a garlic-soy-chili dressing. Here in the U.S., century eggs are almost exclusively black in color with 松花, or “pine flower,” shapes on the egg’s outer surface, formed under the shell by amino acid salt crystals. But during my last trip to China, I was delighted to try preserved eggs of a variety of colors; my favorites were quail eggs with custard-like yellow yolks and clear whites. 

Eggplant-Century Egg Dip: My Twist on Leijiao Pidan Qiezi

The eggplant-century egg dip that I serve at my pop-ups is a variation of a Hunan-style cold dish. The original dish’s name is quite literal: 擂 (léi) refers to the act of mashing in a mortar pestle (or 擂子léizi); 椒 (jiāo) refers to chilies; 皮蛋 (pídàn) to a century egg; and 茄子 (qíezi) to eggplant. In traditional versions of this dish, these three key ingredients are mashed in a large mortar and pestle with garlic and other aromatics, then served at room temperature. Each ingredient maintains most of its structural integrity, and they are easily picked up with chopsticks. Assuming you have a large mortar and pestle on hand, the preparation is pretty straightforward. 

Things get trickier if you don’t have a properly sized mashing device—or when you’re preparing large portions (in my case, making enough to feed 100 people for a pop-up or restaurant takeover). This is why I’ve been using a somewhat unorthodox technique for making this dish: pulsing the ingredients in a food processor to make something more like a dip, instead of making the traditional version that more closely resembles a salad. The result is a deliciously rich, savory snack with an intense kick that’s balanced out with the crispy snap of the cucumbers and radishes that I serve alongside, to scoop up big bites. It reminds me a little of a thicker version of Thai nam prik kapi (a dish made with chilies and preserved seafood), with pungent century egg substituted for the Thai fermented fish or shrimp paste. If I have any leftovers, I use it as a fantastic spread for sourdough or heat it up and turn it into a topping for noodles or rice. It’s a supper club and a household favorite! 

Cooking Tips

There are three main ingredients in this dip (as in leijiao pidan qiezi): eggplant, chili peppers and century egg. The preparation is fairly simple and can be done up to a day in advance.

• First, char the chilies: If you have a gas stove, place the peppers directly on the stove grates over medium-low heat and rotate them constantly over the flame until they have 虎皮 (hǔpí), aka “tiger stripes”:  The whole pepper should be blistered, and the heat from the stove grates should create blackened stripes on the skin. I usually keep some of the charred skin on the pepper (it adds a nice touch of smokiness), but you can remove all the heavily burnt areas if you’d like. Remove the stems, and remove the seeds, too, if you prefer less spice. When I developed the recipe, I used 牛角椒 (niújiǎo jiāo), or green cowhorn (or “ox horn”) peppers (a variety commonly found in NYC’s Chinatown), because they looked fresh at my local produce stand. But I’ve had success using poblanos, too. Use whatever semi-spicy green chili is readily available! 
• Second, prepare the eggplants: Slice them crosswise into 2–3 inch segments and steam them over high heat for 10 minutes, until softened. Let them cool.
• Third, combine everything together: Use a food processor to blend the chilies, eggplants and peeled century eggs into a chunky paste (working one at a time or blending them together). Transfer this paste into a heat-proof mixing bowl and add garlic and ground chili. Heat ⅓ cup of neutral oil (in a wok or a pot) until it is almost smoking and then pour it onto the mixture; this will toast the aromatics. Season the mixture with light soy sauce, Sichuan black vinegar, sesame oil, salt, sugar and MSG. 
• Serve the dip with sliced cucumbers or radishes, or feel free to be creative and incorporate seasonal produce. I like to garnish the dip with a light sprinkle of toasted sesame seeds. 
• Note that this dip starts oxidizing and fermenting pretty quickly, even when refrigerated (within 2–3 days). That said, I’ve never had an issue finishing leftovers within that time frame.

For more flavorful liang ban, check out Zoe’s Five-Spice Beef (Wuxiang Niurou, 五香牛肉) and Qianlong Cabbage (Qianlong Baicai, 乾隆白菜) and Kathy’s Spicy Daikon Carrot Salad (Liangban, 凉拌).