Appetite starts where the pasta is stacked. One documented account builds pasta ’ncasciata as successive layers of macaroni and richly varied additions, each turn of the pasta given company rather than left alone. The recorded layers include aubergine, meatballs, chicken livers, tomato, salami, basil and grated cheese. That is already a generous table written as strata: aubergine beside meatballs and chicken livers, then tomato, salami, basil and grated cheese, waiting in the same construction. Nothing extra is claimed for how they taste together; the invitation is simply to follow those layers with the eye, and to want the next slice because the list itself is so full.
In that version, eggs bind the many components so the finished pasta keeps its moulded form. The craft is quiet and practical: eggs are asked to hold macaroni together with aubergine, meatballs, chicken livers, tomato, salami, basil and grated cheese, so the successive layers do not fall apart when the moulded form is set down. What the account gives is that positive work of holding shape. The moulded form is why the layers are laid as they are, and why approaching the dish still feels like being asked to wait for a clean cut rather than a scatter of pasta.
Another source places this elaborate aubergine-and-pasta preparation within southern Italian and Sicilian cooking. That is culinary context, not a claim that the dish is exclusive, ancient, or made the same way everywhere. Still the placement matters: the elaborate pairing of aubergine and pasta belongs, in that account, to southern Italian and Sicilian cooking, and the reader is left wanting to know how that context meets the layered construction already described.
What remains is curiosity at the slice. Successive layers of macaroni, the recorded company of aubergine, meatballs, chicken livers, tomato, salami, basil and grated cheese, and eggs that keep a moulded form: southern Italian and Sicilian cooking, in the sources we have, offers that much. How those layers meet, once the bind has done its work, is the next thing worth tasting.