Preheat oven to 375°F (190°C). Grease a 9x13 inch baking dish.

Lay eggplant slices on a baking sheet, brush with olive oil, and bake for 15 minutes, or until slightly softened.

In a large skillet, brown the ground turkey over medium heat. Drain off any excess fat. Add chopped onion and cook until softened, about 5 minutes. Stir in minced garlic and cook for 1 minute more until fragrant.

Stir in crushed tomatoes, oregano, basil, salt, and pepper. Bring to a simmer and cook for 10 minutes.

In a medium bowl, combine ricotta cheese, egg, and Parmesan cheese. Mix well.

Spread a layer of meat sauce in the bottom of the prepared baking dish. Arrange a layer of eggplant slices over the sauce. Dollop half of the ricotta mixture over the eggplant. Sprinkle with one-third of the mozzarella cheese.

Repeat the layers: meat sauce, eggplant, remaining ricotta mixture, and another third of the mozzarella cheese. Top with the remaining meat sauce, eggplant, and mozzarella cheese.

Cover the baking dish with foil and bake for 25 minutes. Remove the foil and bake for another 15 minutes, or until the cheese is bubbly and golden brown.

Let stand for 10 minutes before serving.