Preheat the oven to 375°F (190°C).

In a large skillet, heat the olive oil over medium heat. Add the sliced mushrooms and cook for about 5-7 minutes, until they are softened and browned. Stir in the minced garlic and cook for another minute. Add the chopped spinach and cook until wilted, about 2-3 minutes. Season with salt, pepper, oregano, and basil. Remove from heat and let cool slightly.

In a mixing bowl, combine the ricotta cheese and half of the mozzarella cheese. Mix well.

Spread ½ cup of marinara sauce on the bottom of a 9x13-inch baking dish.

Place three lasagna noodles over the sauce. Spread half of the ricotta and mozzarella mixture over the noodles, followed by half of the mushroom and spinach mixture. Pour 1 cup of marinara sauce over the top, then sprinkle ¼ cup of grated Parmesan cheese.

Repeat the layering process: place three more noodles, the remaining ricotta and mushroom-spinach mixture, another cup of marinara sauce, and another ¼ cup of Parmesan cheese.

Top with the final three noodles, the remaining marinara sauce, the rest of the mozzarella cheese, and the remaining grated Parmesan cheese.

Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes. Remove the foil and bake for an additional 15 minutes or until the cheese is bubbly and golden.

Allow the lasagna to cool for about 10 minutes before slicing and serving.