Preheat oven to 425°F. Line a large rimmed baking sheet with foil; set a wire rack on the baking sheet. Cut eggplant lengthwise into 4 (¾-inch-thick) slices, keeping stem intact.
Place panko, flour and egg in 3 separate wide, shallow bowls. Stir Italian seasoning, garlic powder and onion powder into the panko.
Working with 1 eggplant slice at a time, dredge in flour and shake off excess. Dip in egg; let excess drip off. Dredge in panko mixture to coat, pressing to adhere. Place on the prepared rack. (Discard any remaining egg, flour and panko.)
Generously coat the tops of the eggplant slices with cooking spray. Bake until the panko is extra-crispy and browned and the eggplant is tender, about 40 minutes, carefully flipping and coating with cooking spray halfway through. Remove from the oven and sprinkle with salt.
Increase oven temperature to broil; preheat for 5 minutes. Top the eggplant slices with marinara, mozzarella and Parmesan. Broil until the cheeses are melted and browned in spots, 2 to 3 minutes.
Divide the eggplant slices among 4 plates; drizzle with oil. Garnish with basil, if desired.
