Put 1/2 cup of the tomato sauce int he bottom of a 9" x 13" pan.
Next, put down a layer of noodles.
Next, put down a layer of half of the onions & spinach followed by the ricotta and the mushrooms.
Cover with a layer of noodles and more sauce.
Now, top with the zucchini and squash.
Cover with the tomato puree, and then, half the mozzarella.
Now add the 2nd layer of noodles and cover with sauce.
Cover with the remaining onions and spinach.
Cover with the remaining ricotta.
Put most of the remaining sauce on.
Finish with the final noodle layer.
Top with the rest of the sauce, and then, the remaining mozzarella and the fresh mozzarella.
Bake at 325 degrees for 45 minutes covered.
Remove the cover and cook for another 20 minutes.
Serve and enjoy!