A tramezzino al gorgonzola works because a loud cheese has been put inside the quietest possible bread. Gorgonzola is the Lombard blue, veined with penicillium that gives it a sharp, mineral, piquant edge over a fatty lactic base, and dropped into a soft crustless white triangle it has nothing to compete with and everything to colour. The crumb is sweet, airy, and close to tasteless by design; the cheese is salty, funky, and insistent. That gap is the whole point of the build. The bread mutes and carries a flavour that would be overwhelming on a crustier loaf, and the cheese gives the bland white frame the savour it completely lacks on its own. Spread thin and bound smooth, the gorgonzola turns the soft slice into something with a long, pungent finish that the bread alone could never reach.
The craft is matching the form of the cheese to the fragility of the bread. The loaf is a fine soft white sandwich bread, fresh that day, the crust shaved off all four sides so only the tender interior is used, and the slices kept under a damp cloth so they stay supple rather than drying at the edge. A soft gorgonzola dolce is mashed with a little mayonnaise or mascarpone into a spreadable cream so the salt distributes evenly and no single bite turns harsh, which doubles as the bind: the smooth cheese paste films the inner crumb and seals it against the small amount of moisture the cheese carries. That sealing is what lets an oily, assertive filling sit inside a delicate crumb without slumping it. The mixture is built higher toward the centre so the cut triangle stands with a domed middle and a thin closed edge, and a sloppy one shows at once, the spread too thick and salty in one corner, the bread bruised and damp where the cheese soaked through.
The variations stay in the blue family and change one element. There is the build that folds chopped walnut into the cheese for a dry bitter counterpoint, the one that streaks honey through the spread to bridge the salt with sweetness, and the version that leans on the firmer aged piccante crumbled into the mayonnaise so the blue arrives in sharp bursts rather than an even smear. Each of those is the same blue-in-a-soft-dome idea adjusted by a single decision, and each deserves its own article rather than being crowded in here.