The panino con pecorino d'Abruzzo is the mountain reading of Italy's sheep cheese. The pecorino of Abruzzo is made in the high pastures of the Apennine interior, where the flocks graze wild herbs at altitude, and the cheese carries that origin into the sandwich: a firm, dry-ish paste, sharper and more grassy-pungent than a soft table pecorino, with a clean salt edge and a faint bitterness from the mountain herbage the sheep eat. That altitude-driven, herbal sharpness is the whole point of this panino. The bread is a plain crusted roll, there only to carry the wedge, because a cheese with this much grass and salt in it does not need a partner so much as a quiet surface to sit on.
The craft is reading the age and cutting to it. A younger Abruzzese pecorino is semi-firm and tangy and is cut in slabs that bend slightly; an aged one is dry and crumbly and is better broken into rough pieces so it gives a granular bite rather than a rubbery slice. The cheese goes on the bread plainly, the herbal sharpness left to stand on its own; where anything is added it is a counter to the salt, not a competitor to it, a few fresh fava beans in spring or a thread of mountain honey against the bitterness. No oil and no sauce, because the paste is firm and dry and a wet dressing would only mask the grassy note that distinguishes it. The bread is plain and the assembly minimal precisely because the mountain is already loud.
The named directions follow the Abruzzo dairy. There is the very young pecorino fresco eaten with broad beans, the long-aged stagionato that reads almost as a grating cheese broken into shards, and the smoked affumicato of some upland makers with its woody edge. The Filiano and Fossa pecorini are different regional cheeses with their own ageing and are not this. Each of these is its own preparation, and each deserves its own article rather than being crowded in here.