Arrange eggplant slices on paper towels and sprinkle both sides with salt. Let sit for 20 minutes, then pat dry to remove moisture.
Preheat oven to 400°F and line two baking sheets with parchment paper. Mix breadcrumbs with 1/2 cup Parmesan cheese in a shallow bowl.
Dip each eggplant slice in beaten eggs, then coat in breadcrumb mixture. Arrange on baking sheets, spray with olive oil, and bake for 25 minutes, flipping halfway through.
Spread 1 cup marinara sauce in the bottom of a 9x13-inch baking dish. Layer half the eggplant slices, half the remaining sauce, half the mozzarella, and half the remaining Parmesan.
Repeat layers with remaining eggplant, sauce, and cheeses. Sprinkle with oregano.
Bake at 375°F for 30 minutes until cheese is bubbly and golden. Let rest 10 minutes, then garnish with fresh basil before serving.