The panino con bombette is a hot Puglian sandwich whose centre is the bombetta: a thin sheet of pork, usually capocollo, wrapped around a core of cheese and grilled over wood until the meat crisps at the edges and the cheese inside goes molten. They come off the grill at the butcher counters of the Valle d'Itria small, dense, and dripping, and the sandwich is simply the means of getting them from the fire to the hand. What defines it is heat and the burst: a hot, fatty parcel of pork that, when bitten, releases the soft cheese trapped at its core into the bread around it. It is not a cold cured panino. It is a grilled thing eaten the moment it is done.
The craft is timing and a bread that can take the grease. The bombette have to go into the roll straight off the grill, because the entire appeal, the crisp pork exterior against the running cheese centre, lasts only minutes before the parcel cools and the cheese sets back into a firm plug. The roll is plain and sturdy, often split and warmed briefly on the same grill, chosen to absorb the rendered pork fat and the escaping cheese without going limp; a soft delicate bread would dissolve under that load. Little or nothing is added, because the bombetta is already a complete unit of fat, salt, and melt, and a sauce would only mute it. Salt and sometimes a turn of pepper or chilli are worked in at the counter to order. The sandwich is eaten standing, fast, while it is still too hot to be sensible about.
The variations are mostly what is stuffed inside the pork and each is its own preparation rather than a footnote here. There is the version with capocollo layered in alongside the cheese, the one rolled around pancetta, the spicier build worked through with chilli. Other grilled Puglian fornello pronto preparations follow their own logic and deserve their own articles rather than being crowded in here.