Only know one way:
Sauté ed mutton slices with onion
Slice the leg of lamb (if it is not easy to cut, freeze it in the refrigerator for a while), marinate it in starch cooking wine for a while, and then cut the onion. Better have more onions, it's delicious. Cut the onion into hob pieces. It's basically the same size as mutton slices. Put the oil into the pot, it is best to heat the pot and cool the oil, otherwise it will be easy to put it into the pot. Then stir-fry the meat slices quickly, slide them open, and add soy sauce, sugar, salt and a little vinegar after discoloration (this can enhance the taste, but don't overdo it, otherwise it will turn sour). Add onion and stir fry a little. Put monosodium glutamate before cooking. The point of attention is to be quick, because the meat doesn't taste good when it is old. This method can also be used to fry onions and beef.