Begin by washing and chopping all vegetables. This makes the assembly process much smoother.

In a large skillet, heat the olive oil over medium heat. Add the mushrooms, zucchini, and onion, sautéing until tender, about 5-7 minutes.

Once the base vegetables are cooked, add the minced garlic and fresh spinach. Cook until the spinach wilts down, about 2-3 minutes.

Sprinkle salt, pepper, and Italian seasoning over the vegetable mixture. Stir well to combine and then remove from heat.

In a separate bowl, combine the ricotta cheese, half of the mozzarella cheese, and half of the Parmesan cheese. Season with a pinch of salt and pepper, mixing until well combined.

In a baking dish, spread a layer of the cooked vegetable mixture at the bottom. Place 3 sheets of lasagna noodles on top.

Spread half of the ricotta cheese mixture over the noodles, followed by half of the remaining vegetable mixture.

Continue layering with noodles, the rest of the ricotta mixture, and the remaining vegetables. Finish with a final layer of noodles on top.

Cover the baking dish with foil and bake in a preheated oven at 375°F (190°C) for about 25 minutes.

Remove the foil and sprinkle the remaining mozzarella and Parmesan on top. Bake for an additional 15-20 minutes until the top is bubbly and golden brown.