Preparation

• Position racks in the upper and lower thirds of your oven. Preheat the oven to 400 degrees F. Lightly coat 2 rimmed baking sheets with nonstick spray. Coat a 9×13-inch baking dish with nonstick spray and set aside.
• Arrange sliced eggplant in a single layer on the 2 sheet pans. Brush 2 ½ tablespoons of the oil over both sides of all the slices. Sprinkle ½ teaspoon kosher salt and ¼ teaspoon pepper over the top.
• Roast the eggplant until it is soft and golden, about 25 minutes, flipping the slices over and swapping the pans’ positions halfway through. Remove from the oven and reduce the temperature to 350 degrees F.
• Meanwhile, in a large skillet heat the remaining ½ tablespoon oil over medium heat. Add the sliced mushrooms and sauté until soft, about 7 minutes. Add the minced garlic, remaining kosher salt, and oregano. Cook for another 2 minutes. Remove from heat and stir in the marinara sauce.
• In a large bowl, combine ricotta, ¼ cup Parmesan, egg, remaining kosher salt, and remaining ¼ teaspoon pepper. Mix well. Stir in the spinach.
• Spoon half of the mushroom marinara sauce into the prepared baking dish. Layer with 4 eggplant slices, all of the ricotta mixture, another 4 slices of eggplant, and finish with the remaining mushroom marinara sauce and mozzarella. Top with remaining ¼ cup Parmesan.
• Bake for 25 to 30 minutes until the cheese is melted and the lasagna is hot and bubbly. Remove from the oven, sprinkle with fresh herbs, and let rest for 5 to 10 minutes before serving.