In Beijing, it is almost well-known to mention the term "instant lamb". Instant mutton is a cuisine with Beijing characteristics, which is easy to eat and has a delicious taste, making it very popular.

There is also a historical story about its origin.

It is said that in those days, Kublai Khan(忽必烈) commanded a large army to march south. One day, everyone was exhausted and hungry, he suddenly remembered the dish of his hometown - stewed lamb, and ordered his subordinates 部下 to kill the sheep and burn the fire.

Just as the cook was slaughtering sheep and cutting meat, the scout galloped into the tent and reported the enemy approaching. At that time hungry Kublai Khan was waiting to eat lamb. He ordered the troops to pull out, and shouted, "Mutton! Mutton!"

The chef knew that he was irritable, so he quickly came to his senses and cut more than ten thin pieces of meat with a flying knife. He stirred them in boiling water a few times, and when the meat color changed, he immediately took it out of a bowl and sprinkled fine salt.

Kublai Khan repeatedly ate a few bowls and turned over to lead his army to meet the enemy, resulting in victory.

During the celebration banquet, Kublai Khan had the lamb slices made again. This time, the chef selected tender lamb, cut it into thin slices, and paired it with various seasonings. The generals praised it endlessly after eating it, so Kublai Khan named it "boiled lamb", and from then on, boiled lamb became a palace delicacy.

It is said that it was not until the Guangxu period that the old shopkeeper of the "Donglaishun" mutton restaurant in Beijing obtained the seasoning formula for "instant lamb" in the palace, which made this delicacy popular among the people and enjoyed by ordinary people.