Sichuan pepper, or huājiāo (花椒) in Chinese, is one of the most loved, and simultaneously, one of the most hated of Chinese spices. Some abhor its "soapy" aroma and pick out the peppercorns from a dish with distaste; others positively seek them out to enjoy their characteristic numbing flavor to the fullest.
Sichuan pepper appears in many of the most famous Sichuanese dishes, and its flavor is perhaps the most characteristic aspect of the region's cooking: Others, such as Hunan and Guizhou, use just as much chili, but none use huajiao with such a liberal hand as the Sichuanese. It is also worthwhile noting that huajiao's appearance in Sichuan cuisine far outdates that of the chili pepper.
Today, huajiao is most frequently fried with dried chili peppers, a method that brings out its smoky tones (for example in kungpao chicken), but it is also dry-fried and ground to a powder (as in mapo tofu), and even occasionally used raw (as in jiaoma jipian, chicken slices dressed with a Sichuan pepper sauce). Sichuan pepper is also frequently one of the ingredients in the (highly variable) Chinese "five-spice" mixture and is used in various other Asian cuisines, such as Japanese, Korean, and Indonesian.
In spite of its name, Sichuan pepper is in fact related neither to black pepper nor chili peppers, but is the outer husk of the fruit of the prickly ash tree, Zanthoxylum. This somewhat stunted tree (thorny branches bare in the winter, covered by dark green, pale-edged leaves in the summer), produces its harvest in August: slightly knobbly, dusky pink balls, gathered in busy clusters—a stunning contrast to their surrounding dark leaves.
Qingxi village in Hanyuan County (about 300 km southwest of Chengdu) is where the most prized and famous Sichuan pepper is grown. Its history here is long and illustrious; it is mentioned in the foundational Book of Songs, thought to be compiled by Confucius himself, and Qingxi's Sichuan pepper was for many centuries sent in tribute to the imperial court of China's emperors.
When I visited Qingxi, only a few weeks before the harvest, the trees were dripping with the peppercorns, and their lemony aroma reached me before I was close enough to touch them. I learned from villagers that once picked, some of the peppercorns would be used fresh to make huajiao-flavored oil; the rest would be laid out in bamboo baskets under the sun until the skin cracked, revealing the shiny black seeds within. The seeds would then be shaken from the husks and discarded, and the leftover husks are thus ready for use in cooking.
You too can make the several-hour journey to buy Sichuan pepper from the very village where it is produced, but for those not quite as pepper-obsessed as me, just try to buy a brand from Hanyuan County. I also recommend buying Sichuan pepper in pre-sealed packets, not loose, as its flavor diminishes rapidly when not kept in a sealed container. As mentioned earlier, it is delicious fried with dried chili; this method, called qiang in Chinese, can be used in combination with all manner of fresh vegetables. I like it particularly with slithers of round courgette (zucchini).
But perhaps the most famous of Sichuanese dishes that uses Sichuan pepper is mapo tofu, a recipe for which I've adapted from Fuchsia Dunlop's Sichuan Cookery and provided below.
1 block of tofu
3-4 spring onions (scallions)
Vegetable or peanut oil
150g minced beef (optional)
2 Tbsp doubanjiang
1 Tbsp douchi, rinsed and drained
1 tsp sugar
2 tsp light soy sauce
1 tsp doufen mixed with 1 tablespoon of water
1 tsp Sichuan pepper
1. Cut the tofu into 2cm cubes and leave to steep in very hot, salted water. Slice the spring onions into 3cm-long chunks. Dry-fry the Sichuan pepper in a hot wok until smoking, tip out into a pestle-and-mortar and then grind to a fine powder (you can use pre-ground Sichuan pepper, but it won't taste as good).
2. If using the beef, pour about 2 tablespoons of oil into a wok and heat. Once smoking, add the minced beef and fry until a little brown and set aside.
3. Add another tablespoon or so of oil, heat and add the chili-bean paste. Fry for about 30 seconds, taking care not to let it burn, and then add the fermented soy beans and cook for another 30 seconds.
4. Pour in the water, add the sugar, soy sauce and salt to taste and now add the drained tofu cubes. Simmer for about 5 minutes, to allow the tofu to absorb the flavors.
5. Add the spring onions (scallions) and gently stir in. Once they are just cooked, add the starch-and-water mixture to thicken the sauce. Finally, pour everything into a serving dish, scatter with the cooked minced beef and the ground Sichuan pepper, and serve.