Using slicer/shredder disc, shredding side up, shred mozzarella. Place in a small bowl and set aside.
Using S-blade, place onion and garlic cloves into work bowl. Pulse until coarsely chopped. Add mushrooms to bowl. Continue to pulse until mushrooms are coarsely chopped.
Place chopped vegetables in a large skillet with oil, over medium heat.
Using S-blade, place zucchini in work bowl. Pulse until coarsely chopped. Add zucchini to skillet. Cook until tender, about 10 minutes; set aside.
Without washing the work bowl, using S-blade, place Parmesan cheese chunks in bowl and process on High until coarsely chopped. Add the cream cheese, ricotta cheese, sour cream, egg, and Italian seasonings and process until creamy, about 30 to 40 seconds.
Grease a 9x13-inch baking dish. Layer half each of noodles, cream cheese mixture, chopped vegetable mixture, and spaghetti sauce. Repeat layers once. Sprinkle with mozzarella.
Bake, covered, at 350°F for 25 minutes. Uncover and cook an additional 10 minutes. Let stand 10 minutes before serving.
Note: Mozzarella cheese will shred easier if placed in freezer for one hour before shredding.