Preheat oven to 325 degrees. Spray casserole dish with cooking spray, set aside.
Brown hamburger, sausage and onions and drain well, set aside.
In a large bowl, beat egg. Stir in parsley flakes, garlic powder and onion powder. Stir in cottage cheese, parmesean cheese, and 1/2 cup of the mozzarella cheese and set aside.
Begin assembling lasagna by spreading a small amount of spaghetti sauce in the bottom of prepared casserole dish. Layer a few of the lasagna noodles to cover bottom.
On top of noodles, layer one half of the cheese mixture; cover with more noodles. Layer sliced mushrooms. Note: You may also layer spinach, then layer mushrooms on top of spinach, if desired.
Add about 2/3 of the spaghetti sauce to the hamburger mixture and stir. Layer on top of sliced mushrooms. If mixture seems too dry, you may add a little more spaghetti sauce, but note that the mushrooms will lose moisture as they cook. Cover with another layer of noodles.
Layer the rest of the cheese mixture on top of noodles. Cover with more noodles. Add the rest of the mozzarella cheese and sprinkle with more parmesan.
Cover with foil and bake for one hour. Uncover and bake an additional 10 minutes or until cheese is lightly browned.
Let stand for about 20 minutes before serving. Please note that the fresh mushrooms may lose moisture. If you have some excess water when you cut your first serving, you may just spoon it out and discard.