Preheat oven to 350 degrees.
In a large pan, heat the olive oil and sauté the onions for about 3 minutes. Add the sliced mushrooms and cook another 5 minutes on medium heat, stirring continually. Add the spinach, stir until wilted.
Add the tomatoes and tomato sauce. Add favorite Italian seasoning and season the sauce to taste.
Spray a 9×13 baking dish and place 5 sheets of lasagna noodles on the bottom, overlapping one another. Spread 1 cup of the sauce on top, and sprinkle Jack or Mozzarella cheese (or thinly sliced). Next, lay down about 8-12 fresh basil leaves.
Layer again 5 lasagna noodles, 1/2 of the sauce, sprinkle with Parmesan cheese, and repeat this process.
Place remaining sauce on top and sprinkle with 1 cup of Parmesan cheese. Cover the baking dish with foil. Bake lasagna for 40 minutes. Uncover and bake until hot and bubbly, about 20 more minutes.
Let lasagna sit for 10 minutes before serving.