Preheat your oven to 350°F (175°C).

Cook the lasagna noodles as per the package instructions until al dente. Drain and set aside.

In a large pot, heat the olive oil over medium heat. Add the chopped onion and garlic, sautéing until they turn translucent, about 3 minutes.

Incorporate the diced zucchini, chopped bell pepper, spinach, and sliced mushrooms. Season with Italian seasoning, salt, and pepper, and cook until the vegetables are tender, approximately 5–7 minutes.

In a mixing bowl, combine the ricotta cheese, 1 cup of shredded mozzarella, and 1/2 cup of grated Parmesan cheese. Mix until creamy and well blended.

In a prepared 9×13 inch baking dish, spread a layer of béchamel sauce on the bottom.

Layer 3 lasagna noodles on top of the sauce, followed by half of the ricotta mixture, half of the sautéed veggies, and a third of the remaining béchamel sauce.

Repeat the layering: add another 3 noodles, the remaining ricotta mixture, the rest of the veggies, and another third of the béchamel sauce.

Finish with the last 3 noodles, covering them with the remaining béchamel sauce. Top with the remaining mozzarella and Parmesan cheese.

Cover the baking dish with foil and bake for 30 minutes.

Remove the foil and bake for an additional 15 minutes, or until the top is golden and bubbly.

Allow to cool for 10 minutes before slicing. Garnish with fresh basil, if desired.