Bao Du

Bao du, a Beijing late-Qing snack culture dish, was a Hui Muslim trade across Beijing's old quarters such as Niu Jie and Menkuang Hutong; the famous Baodu Feng house itself began as a stall at Houmen Bridge (Di'anmen), not at Niu Jie — when fast-blanched tripe became a cheap, halal, sit-and-go meal. The Feng family stall, opening in the Guangxu era (c. 1888 per Baidu Baike), established the modern dipping-sauce template still used today.

Niu Jie 牛街 Hui Muslim quarter, late Qing — Feng family stall, 1881, set the dipping-sauce template. Lamb tripe has nine sections used; each blanches different — 散丹 7 sec, 肚仁 12 sec, 葫芦 15 sec. A second long and it's rubber.

Beef or lamb tripe, cut into matchstick strips, blanched in boiling water for seven to fifteen seconds — that's the whole cook time. Drained immediately into a bowl, served with a sesame paste dip thinned with chive flower, fermented bean curd, vinegar, and chili oil. The tripe should crunch like crisp celery, not chew like rubber. Cilantro on top. Eaten standing, fast, before it cools.

Timing is the dish: each tripe section (lamb is divided into 9, beef into 4 commonly used: 肚仁/百叶/百叶尖/厚头) has a different optimal blanch — 「散丹」 takes about 5 seconds, 「肚领」 about 7, 「葫芦」/「肚板」 about 8. A second too long and the protein contracts into rubber; a second too short and it's slippery and raw-tasting. Master baodu cooks count by feel and watch the curl, not a timer.