The panino con orecchiette e cime di rapa is the Puglian Sunday plate forced into bread, carbohydrate carrying carbohydrate on purpose. Orecchiette, the small ear-shaped pasta, are dressed with cime di rapa, the bitter turnip tops wilted in oil with garlic and chilli, sometimes with anchovy melted through. It is a finished pasta dish eaten with a fork, not a filling, and putting a scoop of it between two pieces of bread is the kind of southern excess that should not work and does: dense pasta, oily bitter greens, and soft crumb stacking into one deliberately heavy bite. The defining fact is that the filling is a complete plated dish, and the bread is a handle for it rather than a partner with anything to add.
The craft is making a loose pasta dish hold and choosing bread that can take it. The orecchiette are dressed and then drained of their loosest oil, because a wet, slippery pasta will both slide out of the roll and soak the crumb to paste within minutes; the greens are cooked down properly so the bitterness rounds into something savoury rather than rank. The portion is controlled, since an overfilled one fails the moment it is picked up and the whole idea is a plate made portable. The bread is a sturdy crusted Puglian loaf or roll with enough body to stand up to an oily filling, sometimes toasted on the cut faces so the crumb resists the oil for longer. Nothing sharp is added beyond the chilli already in the greens, which stands in for the acid another sandwich would reach for.
The variations stay on the Puglian table and the same pasta-in-bread logic: the build with crumbled hot sausage worked through, the one finished with a sharp shaving of aged pecorino against the bitterness, the version with a heavier slick of anchovy. Each is a different dressing on the same pasta scooped into the same loaf, and each deserves its own article rather than being crowded in here.