The maritozzo salato is the savoury turn of Rome's sweet cream bun, and its defining fact is that the bread stays exactly what it was while everything inside it changes. The maritozzo is a soft, enriched dome, lightly sweet, glossed and tender, normally split along the top and packed with whipped cream. The salato keeps the bun and discards the sugar logic of the filling: the same dome is split and filled with cold cuts, a soft cheese, sometimes a vegetable cream, so a pastry becomes a sandwich without becoming a different bread. The tension between an enriched sweet-edged dome and a savoury, often salty filling is the entire idea.
The craft is making a soft, rich bread carry a savoury load without going to mush. The dome is split most of the way through rather than cut in half so it opens like a hinge and holds its filling without spilling, the same structural trick the sweet version uses for cream. The filling is kept controlled because the crumb is tender and an overloaded bun tears at the seam; mortadella in loose folds, a spoon of soft cheese, a few leaves for a cut. Assembled close to serving, because the enriched crumb stales faster at the cut than a lean roll and the point is the contrast of pillowy bread against a cool savoury centre.
The named turns belong to the contemporary paninoteca and the modern Roman counter: the mortadella dome, the soft-cheese and herb build, the chef's composed version that treats the bun as a plate. Each of those is the same enriched split dome met by a different savoury filling, and each deserves its own article rather than being crowded in here.