The carciofo alla romana is a whole artichoke braised soft, and the panino built on it is defined by the difference between this version and the fried one it is constantly confused with. This is not the carciofo alla giudia, the Roman-Jewish artichoke flattened and deep-fried until the leaves shatter like glass. The romana is the opposite preparation: a tender globe artichoke trimmed down to its edible heart and pale inner leaves, stuffed at the stem end with mentuccia, the wild Roman mint, along with garlic and parsley, then stewed gently stem-up in oil and water until a knife slides through it with no resistance. What goes between the bread is therefore soft, herb-soaked, and faintly bitter, closer to a braise than a salad, and the whole sandwich follows from that softness.
The craft is moisture control and the herb load, because a wet braised vegetable is the hardest thing to put in bread well. The artichoke is drained properly and, ideally, sliced rather than left whole, so it lies flat and the oil it carries glosses the crumb without flooding it. The bread is a plain sturdy roll or a piece of pane casereccio with enough structure to take the slick of cooking oil; toasting the cut faces firms them against the moisture. The mint and garlic packed into the artichoke are doing all the seasoning, which is why nothing sharp is added on top: a carciofo alla romana arrives already complete, and an aggressive cheese or a vinegar dressing would only argue with the mentuccia. It is eaten at room temperature, never fridge-cold, when the oil reads soft and the herb is most forward.
The variations are mostly about what is allowed to sit beside the artichoke rather than the artichoke itself. There is the plain build of nothing but the sliced romana and its oil, and there are versions that add a thin slice of a mild cheese or a few leaves of green to bridge it to the bread. The fried Roman-Jewish artichoke is a separate preparation and a separate sandwich entirely, and other cooked-vegetable panini across central Italy follow their own logic. Each of those deserves its own article rather than being crowded in here.