Mortadella asks the piadina for warmth above all else, because warmth is what releases it. Cold, the cured pork is pleasant but muted; against the residual heat of a just-griddled Romagnolo round its fat softens and its perfume opens, the gentle spice and the pistachio lifting as the slices slacken inside the fold. That is the defining move of this build. The flatbread is thin, blistered, and still soft, and folded around loose ruffles of mortadella it turns a flat deli slice into something aromatic and almost creamy, the bland fatty crumb giving the delicate meat a quiet, steady base to sit on rather than competing with it.
Done well, it is about texture and temperature, not richness piled on richness. The dough is the standard Romagnolo one, flour with lard or oil and barely any leavening, rolled thin and cooked dry and hot until it freckles dark and stays pliable, lifted off the plate before it crisps to a snap. The mortadella is sliced thin and folded into airy waves, never stacked flat, so it keeps lift and the fat does not pool into a heavy band. Some cooks add nothing else; others slip in a thin layer of squacquerone or a few flakes of grana to sharpen the sweetness. The round is folded in half and eaten at once, while the warmth is still working on the meat and the bread is still soft at the crease.
The close cousins are a single swap from here and stay in the same kitchen. There is the version layered with creamy stracciatella for extra dairy roundness, the one that trades plain mortadella for a coarser pistachio-studded cut, and the simpler fold of cured ham instead of mortadella for a saltier, less perfumed read. Each is the same warm round meeting one changed filling, and each deserves its own article rather than being crowded in here.