The panino con grana padano is the everyday hard cheese standing in for the famous one. Grana Padano and Parmigiano-Reggiano are close cousins, both grainy aged wheels broken into shards rather than sliced, but they are not the same cheese: Grana comes from a larger zone across the Po valley, is generally aged less, and reads milder, gentler, and rounder, with less of the crystalline sharpness that defines a long-aged Reggiano. The sandwich leans into exactly that difference. Where a Parmigiano panino is a deliberate hit of intensity, this one is the softer, more forgiving member of the family, and the defining choice is using the cheese whose flavour does not dominate so completely.
The craft is the cut and the restraint. Grana is never laid on as a flat slice; it is shaved into thin curling flakes with a blade or split into rough shards with the almond-shaped coltello a mandorla, so it crumbles in the bite and its grain registers as texture rather than a slab. Shaved thin it folds into the bread and distributes; broken into thicker shards it gives a harder, more punctuated bite. The bread is plain and sturdy, because even the milder Grana is loud enough to lead and an assertive loaf would only compete with it. The classic counter is a single sweet, acidic note: a few drops of aged balsamic, a thin slice of pear, sometimes a little honey, enough to lift the salt without turning the sandwich into a composed plate.
The variations are the wider hard-cheese counter, each its own preparation rather than a footnote here: the sharper, longer-aged wedge taken as a Parmigiano panino, Grana against pear or balsamic, and the broader Italian habit of building a panino around one wheel at its right ripeness. Each is one hard cheese given a bread, and each deserves its own article rather than being crowded in here.