The panino con robiola is built on a soft fresh Piedmontese cheese whose whole job is to spread. Robiola is a broad family of young soft-paste cheeses from the northwest, made from cow's, sheep's, or goat's milk or a blend, eaten within days of being made: pale, creamy, faintly tangy, soft enough to smear with a knife. It is the spreadable end of the Italian cheese counter, and the sandwich treats it accordingly. Where an aged wheel is sliced and a blue is crumbled, robiola is applied like a rich, mild base layer, which makes the build a question of what one thing you put against the cream.
The craft is using a soft fresh cheese so its mildness is an asset rather than a blank. It is spread thick onto a plain or lightly toasted bread, taken just cool so it slackens toward a cream and the gentle tang opens; spread thin it vanishes, and a strong loaf would smother it. Because robiola is rich and quiet, it carries one assertive partner cleanly without a fight: a few folds of speck or prosciutto whose salt and smoke cut the cream, a spoon of mostarda or honey for a sweet counter, a grilled vegetable for char and contrast. The discipline is the familiar Italian one of one creamy cheese as the foundation and a single decisive thing laid on it, not a stack of competing flavours.
The variations follow the cream and its one partner, each its own preparation rather than a footnote here: robiola with speck for the salt-and-smoke build; the sweet version with honey or mostarda; and the grilled-vegetable reading where char cuts the richness. The goat-and-sheep Piedmontese Robiola di Roccaverano DOP is a distinct, tangier cheese with its own treatment and deserves its own article rather than being crowded in here.