Preheat oven to 350°F (175°C) and lightly grease 9x13 inch baking dish. Cook lasagna noodles according to package instructions until al dente, drain in colander, and set aside with light drizzle of olive oil.

Heat olive oil in large pot over medium heat. Add chopped onion and garlic, sautéing until translucent and fragrant, about 3 minutes.

Add diced zucchini, bell pepper, spinach, and mushrooms. Stir in Italian seasoning, salt, and pepper. Cook until vegetables are tender, 5-7 minutes. Remove from heat and let cool 5 minutes.

In mixing bowl, combine ricotta cheese, 1 cup mozzarella, and 1/2 cup Parmesan cheese. Mix well to create creamy cheese layer.

Spread 1 cup béchamel sauce in prepared baking dish. Place 3 lasagna noodles on top, then layer half the ricotta mixture, half the cooled vegetables, and 1 cup more béchamel sauce.

Repeat layers: 3 more noodles, remaining ricotta mixture, remaining vegetables, and another cup of béchamel sauce.

Top with last 3 noodles, remaining béchamel sauce, and sprinkle remaining mozzarella and Parmesan cheese on top until completely covered.

Cover tightly with foil and bake 30 minutes. Remove foil and bake additional 15 minutes until top is golden brown and bubbling. Internal temperature should reach 165°F. Cool 15 minutes before slicing.