01 - Preheat oven to 400°F. Line two baking sheets with parchment paper and lightly coat with olive oil spray or oil.
02 - Arrange eggplant slices on a wire rack or paper towels. Sprinkle both sides generously with kosher salt and let stand for 20 minutes to draw out excess moisture. Pat dry thoroughly with paper towels.
03 - Place flour in one shallow bowl, beaten eggs in a second bowl. In a third bowl, combine breadcrumbs, 1/2 cup Parmesan, oregano, and black pepper.
04 - Dredge each eggplant slice in flour, shaking off excess. Dip into beaten eggs, then press into breadcrumb mixture to coat evenly. Place breaded slices on prepared baking sheets.
05 - Lightly spray or drizzle olive oil over breaded slices. Bake for 20 minutes, flipping halfway through, until golden brown and crispy.
06 - Reduce oven temperature to 375°F. Spread 1/2 cup marinara sauce in the bottom of a 9x13-inch baking dish. Layer half the baked eggplant over sauce. Top with half the remaining marinara and half the mozzarella. Repeat layers with remaining eggplant, sauce, and mozzarella. Sprinkle with 1/3 cup Parmesan.
07 - Bake uncovered for 20 to 25 minutes until cheese is melted and golden brown.
08 - Let rest for 10 minutes before serving to set. Garnish with fresh chopped basil if desired.