Cacioricotta is defined by being made two ways at once, which is why it behaves like neither cheese nor ricotta. The milk, usually goat or sheep in Puglia and the South, is heated very hot the way ricotta is made, then also rennet-set the way a cacio is, so the curd carries both processes. The result is a cheese that is firm and dry rather than wet and spoonable like true ricotta, with a clean, faintly tangy, milky flavour and a granular body that crumbles or grates rather than slicing or melting. Fresh, it is soft and mild and eaten within days; aged a few weeks or months, it dries hard and sharpens into a grating cheese. The panino con cacioricotta, a sandwich of the Puglian larder, is a frame for that crumbly cheese at a chosen point on its short arc from fresh to hard.
The craft is matching the age and the crumble to the bread and the dressing. Young cacioricotta is broken into soft pieces or spread thickly, mild enough to be the quiet centre, and is classically met with a ripe tomato and a hard pour of olive oil so the acid and the fat carry a cheese that does not bring much salt or punch of its own. Aged cacioricotta is grated or shaved in fine flakes, dry and sharper, and used in a smaller, more savoury amount, often against a stronger crusted bread. The bread leans toward the dense Pugliese loaf, pane di Altamura or a country bread with crust enough to take a crumbling, oil-dressed filling without going slack. The dressing matters because the cheese is mild: tomato, oil, salt, sometimes a leaf of basil, all doing the lifting the cheese will not do on its own. It is assembled close to eating, while the crumb is dry and the tomato has not flooded it.
The variations stay close to the cheese and its fresh-to-aged range: the soft young build with tomato and oil, the aged grated form used almost as a seasoning over greens or vegetables in bread, the version on dark durum bread. Each is one point on the same short arc, and each deserves its own article rather than being crowded in here.