Pane carasau con pomodoro turns on softening a sheet of bread that arrives as hard as parchment. Pane carasau is the Sardinian shepherd's bread: a round of dough baked, split into two wafer-thin discs, and baked a second time until each sheet is brittle, dry, and able to keep for months. As it comes it is a cracker, not a sandwich. To make this version you wet the sheet, with water or directly with crushed tomato and oil, just enough that the parchment relaxes and becomes pliable without going to mush. Olive oil and ripe crushed tomato are then worked over it with salt, and often the softened sheets are layered. The defining fact is that the bread is the entire texture of the thing: a sheet revived to the point where it yields but still carries a faint crispness at the edge.
The craft is the wetting and the restraint that has to follow it. The sheet drinks fast because it is so thin, so the moisture is added in a measured way and not left to pool, since a pane carasau given too much water collapses into paste and one given too little stays a shard that scrapes the mouth. The tomato is crushed by hand so its own juice does part of the softening from above while the oil slicks the surface, and the dressing is kept to tomato, oil, salt, and sometimes a little dried oregano, because the point is to taste a revived bread and a ripe tomato rather than to bury either under anything heavier. It is dressed and eaten promptly, while the contrast between the softened centre and the firmer rim is still there and before the whole sheet goes slack.
The named turns stay in Sardinia and on the same brittle bread: pane carasau draped instead with prosciutto, where the bread is left crisp under cured meat rather than softened with tomato, and the cooked pane frattau and oiled pane guttiau that revive the identical sheet by other means. Each of those is the same Sardinian parchment treated a different way, and each deserves its own article rather than being crowded in here.