Slice the eggplant into 1/2-inch rounds. Arrange on a tray or baking sheet, sprinkle lightly with salt, and let sit for 20 minutes to draw out excess moisture. Pat dry very well with paper towels.
Preheat the oven to 400°F (205°C). Line two baking sheets with parchment (or foil). For extra crisping, place a wire rack on each sheet.
Set up a breading station: Bowl 1—flour mixed with black pepper and a pinch of salt. Bowl 2—beaten eggs. Bowl 3—panko mixed with 1/2 cup Parmesan, garlic powder, and dried oregano.
Bread the eggplant: Dip each slice in flour (shake off excess), then egg, then press firmly into the panko-Parmesan mixture to coat well.
Arrange breaded slices in a single layer on the prepared baking sheets. Lightly spray the tops with cooking spray (or olive oil spray) to help them brown.
Bake for 20 minutes. Flip the slices, spray the second side lightly, and bake 15–20 minutes more, until golden and crisp and the eggplant is tender.
(Optional) For a cheesy finish, sprinkle with mozzarella and the remaining Parmesan and bake 3–5 minutes, just until melted.
Rest 5 minutes before serving. Serve warm with marinara for dipping and sprinkle with chopped fresh basil, if using.