The panino pugliese is a sandwich about the spiced pork of Puglia meeting the region's fresh stretched-curd cheese, and what defines it is capocollo against burrata. Pugliese capocollo, the dry-cured pork collar of the Murgia, is sweet, lightly spiced, and marbled so it eats soft and rich. Burrata, the bag of mozzarella curd filled with cream and shreds, is cool, milky, and barely holding together. Neither makes the sandwich alone: the capocollo is fat and salt and warm spice, the burrata is cream and quiet and almost no salt, and the whole point is the way the cool cream rounds off the spiced pork while the meat gives the cream a savoury frame so it does not read like a spoon of dairy on bread.
The craft is moisture management, because burrata is a famously wet cheese. The loaf is the Pugliese standard, a hard-crusted pane di Altamura or a sturdy roll with a tight gold crumb, chosen specifically because it can stand up to cream without dissolving. The burrata is torn open and drained of its loosest liquid before it goes in, then laid so the cream is held by the meat and the crumb rather than running out the side; some builders set it against the dry side of the bread to buy a few minutes of structure. The capocollo is sliced thin and folded loose so its fat warms and binds the cream to the crumb. The sandwich is dressed only with good oil and perhaps a turn of pepper, eaten soon after building, before the cheese has time to slacken the bread that is holding it up.
The variations stay in Puglia and turn on which element leads. There is the build that swaps burrata for a firmer mozzarella di Gioia del Colle for a drier, more portable bite, the one weighted to the capocollo with the cheese used only as a cooling streak, and the version that adds bitter cime di rapa to push against the richness. Each is the same spiced-pork-and-fresh-cheese logic with one element moved, and each deserves its own article rather than being crowded in here.