Saute 1/3 onion in oil or water for 1 minute or until translucent. Add 1/3 garlic and cook for 1 minute then add mushrooms and cook another 2 minutes or until the mushrooms are soft. Remove from pan and set aside. Put another 1/3 of the onion and 1/3 garlic in the same pan and cook for one minute. Add zuc-chini and parsley and cook for another minute. Remove from pan and set aside. Do the same with the remaining onion, garlic and spinach.
Heat tomato sauce in another pan and add basil and oregano. Simmer for 2-3 minutes.
Boil the noodles as per directions, drain well. Heat the oven to 375°F In a rectangular baking dish, pour 3/4 cup of the tomato sauce and lay about 3 of the lasagna noodles to cover the bottom of the dish. Spread 1/2 the spinach on top. Arrange another 3 pieces of lasagna and spread the mushroom mixture on top. Add a bit of the sauce and arrange another 3 pieces of lasagna noodles on top. Next, spread the zucchini mixture and add the remaining spinach on top. Finish with the remaining lasagna noodles and pour the remaining sauce on top.