Preheat and Prepare Eggplant
Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper. Arrange the eggplant slices on the sheet, brush with olive oil, and sprinkle with salt and pepper. Roast for 15-20 minutes, flipping halfway through, until the eggplant is tender and slightly golden. Remove from the oven and set aside.
Prepare the Ricotta Mixture
In a bowl, combine the ricotta cheese, egg, Parmesan cheese, and Italian seasoning. Stir until smooth and set aside.
Assemble the Lasagna
Spread a thin layer of marinara sauce on the bottom of a 9x13-inch baking dish. Place a layer of roasted eggplant slices on top, followed by a layer of the ricotta mixture, a sprinkle of mozzarella, and a spoonful of marinara sauce. Repeat these layers, finishing with a layer of marinara sauce and topping with the remaining mozzarella.
Bake
Cover the dish with foil and bake for 25 minutes. Then remove the foil and bake for an additional 15-20 minutes, until the cheese is bubbly and golden.
Serve
Let the lasagna cool for 10 minutes before slicing. Garnish with fresh basil and serve warm.