It is a 14 to 21 oz (400 to 600g) piece of pork, whose shape is somewhat like a cone cut in half through the top.
It is cut from the lower portion of a cheek of a pig.
You can buy them raw at some butchers, but they are usually sold prepared and cooked. The meat is boned, and brined (they used to be dried as well.) The cone shape comes from a special mould that the boned, brined cheeks are pressed into. They’re left in the moulds for a while, then removed, whereupon they retain their shape, and then they are dusted with bread-crumbs, ready for slow cooking until the meat is tender.
When the prepared Bath Chap is cut into, you see streaks of white fat and pinkish lean meat. It tastes a bit like a ham from the brining.
Some are sold now already breaded and cooked. These can be served cold, as you would ham.
Bath Chaps were originally made from the breed of pig called “Gloucestershire Old Spot”, a pig whose skin was dappled with black spots.
The breed almost died out.
The pigs were allowed in the fall to eat the fallen fruit in apple orchards, which made the flesh sweet.
In the 1500s, a “chop” meant the jowls of a pig. The slang expression “slap you in the chops” that is still used by some actually dates back to this. “Chap” is a variation of “chop.”
Sometimes, “Bath Chap” was used to refer to just a raw, unprocessed pig’s cheek, as in Mrs Beeton’s advice: “A pig’s cheek, or Bath chap, will take about 2 hours after the water boils.”
They may be referred to also just as “chaps”.
Fearnley-Whittingstall, Hugh. Hugh Fearnley-Whittingstall’s ox tongue, oxtail and pigs’ cheek recipes. Manchester, England: The Guardian. 7 May 2011.