Preheat your oven to 425°F (220°C). In a large mixing bowl, toss sliced zucchini, red bell peppers, yellow bell pepper, red onion, and mushrooms with olive oil, salt, black pepper, and dried oregano. Spread the vegetables on a baking sheet in a single layer. Roast for about 20-25 minutes, stirring halfway through.

While the vegetables roast, prepare the ricotta filling. Combine ricotta cheese, eggs, a pinch of salt, and grated Parmesan cheese in a medium bowl. Mix until smooth.

If using traditional noodles, bring a large pot of salted water to a boil and cook noodles according to the package instructions, usually around 8-10 minutes. Drain and rinse under cold water.

In a 9x13-inch baking dish, pour a thin layer of marinara sauce on the bottom. Layer three cooked noodles, half of the roasted vegetables, one-third of the ricotta mixture, a sprinkle of mozzarella, and more marinara. Repeat until all ingredients are used, finishing with noodles, sauce, mozzarella, and remaining Parmesan cheese.

Cover the lasagna with aluminum foil and bake in the preheated oven at 375°F (190°C) for 30 minutes. Remove foil and bake an additional 15-20 minutes until cheese is bubbling and golden brown.

Allow lasagna to rest for 10-15 minutes before cutting. Garnish with fresh basil if desired.