01 - Preheat the oven to 400°F (200°C).
02 - Arrange zucchini, eggplant, bell peppers, and mushrooms on a baking sheet. Drizzle with olive oil, sprinkle with oregano, basil, salt, and pepper. Roast for 20 minutes until tender.
03 - If using regular lasagna noodles, cook according to package instructions. Drain and set aside.
04 - In a mixing bowl, combine ricotta cheese, egg, half of the grated Parmesan, salt, and pepper. Mix thoroughly.
05 - Heat a splash of olive oil in a large skillet over medium heat. Sauté diced onion and minced garlic until softened, about 3 minutes. Add roasted vegetables, cook an additional 2 minutes, then remove from heat.
06 - Spread one-third of the marinara sauce on the bottom of a 9x13 inch (23x33 cm) baking dish. Lay 3 lasagna noodles over the sauce.
07 - Top noodles with half of the ricotta mixture, half of the sautéed vegetable mixture, and one-third of the shredded mozzarella.
08 - Repeat layering with one-third of the marinara sauce, 3 noodles, remaining ricotta mixture, remaining vegetables, and one-third mozzarella.
09 - Add remaining 3 noodles, spread remaining marinara sauce on top, then sprinkle with remaining mozzarella and Parmesan cheese.
10 - Cover the dish with aluminum foil and bake for 25 minutes.
11 - Remove foil and bake for an additional 15 minutes until the cheese is bubbling and golden.
12 - Allow the lasagna to rest for 10 minutes before slicing. Garnish with fresh basil.