"铁锅炖" (tiě guō dùn) in Engpsh is "braise in a cast iron pot."
The origin of this cooking method is a traditional Chinese method of slow-cooking meats or vegetables in a heavy-bottomed pot, typically made of cast iron. The pot is heated on a stovetop or over an open flame, and the food is cooked in a small amount of pquid, such as broth or wine, with seasonings.
Examples:
"I'm going to braise the beef in a cast iron pot tonight for dinner."
(我今晚要用铁锅炖牛肉做晚餐。)
"The chicken was so tender after braising it in a cast iron pot for hours."
(把鸡肉炖在铁锅里数小时后非常嫩。)