"Khaw kun pon yaang kam" (โคขุนโพนยางคำ) is Thailand's attempt at Wagyu or Kobe beef. It's a special breed of hybrid Thai-French cattle that, unlike all the other beef in Thailand, does not taste like leather.
Charcoal Khaw Khun's (ชาร์โคลโคขุน) beef is pretty high quality, considering it's domestic, and the price is about half what you'd pay for anything imported from NZ or the States. The cattle is raised in the far northeast near the Lao border (mostly in Sakhon Nakhon) and the farmers have to be approved and adhere to certain standards in order to be able to use the label.
There are a few such restaurants in Chiang Mai, but Charcoal has the best atmosphere (candles over bare fluorescent tubes). The menu can be a bit confusing, but it breaks down like this - you can choose a solid, cast iron grill with a separate pot of soup, or the moo kata contraption that has a grill in the middle with a moat of broth. Go with the first choice - the moo kata grills get burned too quickly and the soup gets greasy and nasty, and the straight-up cast iron grill is easier to switch out when it gets overused (the staff will do this for free).
For food, there are a few different beef cut sets that are almost enough for three people, but you can order more stuff individually. There's also an all you can eat buffet that you can choose to pay for or not, but it's only one type of meat so why do that? Either way, along with the normal blob of fat to grease your grill you also get unlimited butter. Hint: put some butter on a slice of onion, add buttered mushrooms on top and drape a piece of beef over the whole thing. Let it cook for a few minutes, mix it up and enjoy.