Old Beijing Copper-Pot Mutton Hotpot (Shuan Yangrou)

Whereas Chongqing and Sichuan hotpot overwhelms the palate with fiery beef tallow and numbing red chillies, Old Beijing copper-pot mutton hotpot (Lao Beijing Tongguo Shuan Yangrou) is the exact opposite: an exercise in pure ingredient quality where the cooking medium is nothing more than clear spring water tossed with two slices of ginger, three segments of white scallion and a few red goji berries. Because the broth is completely unseasoned, only sweet, grass-fed sheep raised on the alkaline pastures of Xilin Gol and Ulanqab in Inner Mongolia, completely free of gamey odour, can pass the test.

The charcoal chimney pot and hand-sliced cuts

At the centre of the table stands a tall, polished brass or copper pot shaped like an upside-down hat wrapped around a central conical chimney stuffed with glowing red fruitwood charcoal. Unlike electric induction plates, the tall copper flue heats the surrounding ring of water to a rolling boil in seconds. Order a mix of hand-sliced fresh lamb (shouqie xian yangrou), the test of freshness is that the chef can turn the wooden platter completely upside down without the raw meat sliding off, and paper-thin machine-shaved rolls:

• Huangguayiao (Cucumber Strip) and Shangnao (Upper Neck): tender ribbons running along the spine with a delicate rim of snow-white fat.
• Yangweiyou (Sheep Tail Fat): swish two translucent white slices through the boiling water first to coat the surface lightly and season the broth before dipping lean cuts.
• Tripe (ba, baidu) and frozen tofu: finishes the meal alongside crisp napa cabbage, crown daisy greens (tonghao) and mung-bean vermicelli noodles, followed by a freshly baked sesame shaobing flatbread.

Mastering the "Erba" sesame sauce bowl

The soul of Beijing hotpot lies in its rich, velvety dipping bowl: Erba (80 percent roasted white sesame paste blended with 20 percent peanut butter), thinned slowly with warm water and seasoned with a crimson cube of fermented red bean curd (furu), emerald-green leek flower paste (jiucaihua), sesame oil, chopped coriander and scallions. Never dump the whole plate of lamb into the pot at once: hold two or three slices in your chopsticks and swish them back and forth (shuan) for just six to eight seconds until the pink vanishes, dip generously into the sesame sauce, and bite into a clove of sweet-and-sour pickled sugar garlic (tangsuan) to cut the richness. Top institutions include Ju Bao Yuan in the Niujie Muslim Quarter, Nanmen Shuanrou near the Temple of Heaven, and historic Donglaishun on Wangfujing.