1) Cut the aubergine in half crosswise. Then cut each half lengthwise into 1cm-thick slices (about 16 slices). Arrange the aubergine slices on several baking sheets and sprinkle generously all over with kosher salt. Set aside to let the bitter juices weep from the aubergine, about 1 hour.
2) Transfer the aubergine to a colander in the sink, and rinse well under cold running water. Transfer eggplant to a work surface and blot very dry with paper towels.
3) In a large bowl, whisk together the 1 1/2 teaspoons salt, breadcrumbs, oregano, thyme, and season with pepper to taste.
4) Place the flour in a medium lipped plate or bowl. In another medium bowl, whisk the egg and milk together. Dredge an aubergine slice in the flour, then dip it in the egg, and finally dredge it in the breadcrumb mixture. Shake off any excess breading and transfer the aubergine to a baking sheet. Repeat with the remaining aubergine.
5) In a large straight-sided skillet, pour the oil to a depth of 1-cm. Heat the oil over medium heat until it registers 200C on a deep frying thermometer. (The oil must be heated to 200C since when the breaded eggplant is added it drops the temperature to the proper frying temperature of 190C)
6) Working in small batches, fry the aubergine slices, turning once, until golden brown, about 3 minutes per batch. Using tongs, transfer to a paper towel-lined baking sheet and season with salt to taste. Repeat with the remaining aubergine. The aubergine can be fried up to 2 hours before serving.
7) When ready to serve preheat the grill. Arrange the hero rolls, split-side up, on a baking sheet and toast under the grill.
8) Cover each roll with about 4 slices of aubergine, overlapping them slightly. Cover each of the aubergine heroes with about 175ml of the sauce, sprinkle with 1 tablespoon Parmesan, and cover with 4 slices of the provolone. Broil until the cheese is melted and lightly browned. Close the hero rolls and slice in half crosswise. Serve immediately.
9) To make the quick marinara sauce: Heat the oil in a medium saucepan over medium-high heat. Saute the onion and garlic, stirring, until lightly browned, about 3 minutes. Add the tomatoes and the herb sprigs and bring to a boil. Lower the heat and simmer, covered, for 10 minutes.
10) Remove and discard the herb sprigs. Stir in the salt and season with pepper to taste. Use now, or store covered in the refrigerator for up to 3 days, or freeze for up to 2 months.