The panino con gorgonzola is held back by exactly one decision: which gorgonzola. The cheese comes in two states that behave like different ingredients. Gorgonzola dolce is young, pale, and so soft it is nearly a spoonable cream, mild and sweet with only a faint blue note; gorgonzola piccante is aged longer, firmer, drier, shot through with green veining and a sharp, almost peppery bite. The sandwich is decided the moment you choose between them, because the dolce spreads and the piccante crumbles, and everything else in the build follows from that. This is the whole logic of the panino: one cheese at one ripeness, and the discipline not to reach for a second strong thing.
The craft is matching that texture to the bread and the moment. Gorgonzola dolce is spread thick onto a soft or lightly toasted bread where its richness can sit without sliding off; piccante is crumbled so its salt and its sharpness distribute through the bite rather than landing in one corner. The cheese wants to sit a little below fridge-cold, when the dolce slackens toward a cream and the piccante stops being brittle, which is when the blue reads at its fullest. The bread is plain and not too assertive, because the cheese is loud on its own and a strong loaf would only fight it. The single classic counter is a sweet one: a smear of honey or a slice of pear against the dolce, a few walnuts against the piccante, just enough to answer the salt.
The variations are the obvious sweet and nutty pairings, each its own preparation rather than a footnote here: gorgonzola with walnuts, the Gorgonzola e Noci; gorgonzola with pear, the Gorgonzola e Pere; and the provenance reading of the cheese from its production heartland, the Gorgonzola di Novara. Each is one blue given a bread and one counter, and each deserves its own article rather than being crowded in here.