Prepare the Eggplant: Wash and slice the eggplants into even slices. Lightly sprinkle both sides with salt and let them sit for about 10–15 minutes. Pat the slices dry with paper towels to remove excess moisture.
Roast the Eggplant: Preheat the oven to 425°F. Arrange the eggplant slices on a baking sheet and lightly brush them with olive oil. Roast for about 20–25 minutes, turning halfway through, until tender and lightly browned.
Prepare the Ricotta Mixture: In a mixing bowl, combine the ricotta cheese, egg, minced garlic, Italian seasoning, salt, black pepper, and half of the Parmesan cheese. Stir until smooth and well combined.
Begin Layering: Spread a thin layer of marinara sauce across the bottom of a 9×13-inch baking dish. Arrange a layer of roasted eggplant over the sauce.
Add the Cheese Layers: Spread some of the ricotta mixture over the eggplant. Sprinkle with mozzarella and add another layer of marinara sauce.
Repeat the Layers: Continue layering the roasted eggplant, ricotta mixture, mozzarella, and marinara sauce until all the ingredients are used. Finish with marinara sauce, the remaining mozzarella, and Parmesan cheese.
Bake the Lasagna: Cover the baking dish loosely with aluminum foil and bake at 375°F for about 30 minutes. Remove the foil and continue baking for another 15–20 minutes, or until the cheese is melted, bubbling, and golden.
Rest and Garnish: Remove the lasagna from the oven and let it rest for about 10 minutes before slicing. Garnish with fresh basil and additional Parmesan if desired.