The eggplant parm hero is the New York reading of the meatless parm, and the word hero is the most local thing about it: the same fried eggplant, marinara, and mozzarella that New England calls a grinder, built on a length of Italian bread with a real crust. The crust is the defining engineering. It has to carry a hot, saucy, water-shedding filling without folding in the middle, and the New York version leans on a sturdier, more structured loaf than the soft sub roll precisely because eggplant releases moisture and the bread is the spine that has to outlast it.
The craft is in defending that crust. The eggplant is salted to draw water before it is breaded, then fried hot so the coating sets into a shell rather than a sponge. The Italian roll is split and given a quick toast so the interior firms into a barrier against the sauce instead of drinking it. The marinara is kept tight, the mozzarella laid thick enough to melt into a binding sheet over the eggplant, and the assembled hero finished under heat just long enough to fuse the layers without saturating the loaf. Built right, the cross-section reads in distinct layers: the fried crust holding its snap, the soft eggplant behind it, the cheese gluing the structure, and a roll that still has enough chew to be picked up at the last bite rather than surrendering halfway.
The variations stay close to the form. A version uses thin-shaved fried eggplant for more coating per bite; another stacks fresh mozzarella over grated pecorino for stretch against sharpness; a baked version drops the fried shell for a softer build. The chicken parm and meatball heroes are the carnivorous cousins on the same loaf, running identical logic with a different center. Each of those is its own build and deserves its own article rather than being crowded in here.