The panino con pecorino di Filiano is the Basilicata reading of the sheep cheese, defined by where and how it is aged. Pecorino di Filiano is a protected cheese from the Filiano area on the slopes of Monte Vulture, made from raw sheep's milk and matured in natural caves, sometimes rubbed with olive oil and wine lees as it ages. That cellar treatment is the whole sandwich. It gives a hard, compact paste that is deeply savoury, slightly piquant, and carries a damp, mineral note from the cave that a dairy-aged pecorino does not have. The bread is a plain crusted roll, present only to hold the cheese, because a wheel matured this way is intense enough that a second strong element would simply argue with it.
The craft is reading the maturation and cutting to suit it. A Filiano taken younger is firm and nutty; a long-cave-aged one is hard, dry, and sharply piquant, and is better broken into rough shards than sliced flat so each piece delivers a concentrated burst. The oil-and-lees rubbing leaves the rind earthy and the paste faintly oily near the edge, so the cheese needs nothing added to round it; where a partner appears it is a sweet counter to the piquancy, a little local honey or a few drops of vincotto from the same Vulture vineyards. No dressing, because the paste is hard and assertive and oil would blur the mineral edge that is the point. The bread carries; the cave-aged wedge is the whole statement.
The named directions stay on Monte Vulture and its dairy. There is the young table version eaten with fresh broad beans, the deeply aged grating-hard wheel broken into splinters, and the pairing with the area's Aglianico-adjacent sweet condiments. The Abruzzo mountain pecorino and the pit-aged Fossa are separate cheeses with their own logic and are not this. Each of these is its own preparation, and each deserves its own article rather than being crowded in here.