Brown the Italian sausage in a large skillet. When done, drain and transfer the sausage to a cutting board. With a sharp knife, finely chop the sausage and then set aside.
Using a large saucepan, open 2 tubs of Buitoni alfredo sauce and pour into the pan. Simmer on medium-low heat until warm.
While the alfredo is warming, finely chop the mushrooms, onion, and fresh garlic.
In a large pan, saute on medium heat for 5-6 minutes. Add in the chopped Italian Sausage and saute for another 5-6 minutes until the mushrooms and onions are tender. Set aside. Now it's time to prepare the ricotta cheese. Put the ricotta cheese, oregano, basil, and Italian seasoning in a medium bowl and mix well with an electric mixer on low speed, about 30 seconds. Set aside.
It's now time to start the layering process. First, add a ½ cup of the warmed alfredo sauce to the bottom of a 13x9 oven safe pyrex dish. Expert Tips: This will ensure the noodles don't stick to the bottom of the dish. Then, place 3-4 lasagna noodles on top of the sauce. From there, add half of the ricotta cheese on top of the lasagna noodles and spread evenly using a basting brush.
Layer half of the spinach on top of the ricotta cheese and spread evenly.
Next, add half the sausage, onion, mushroom, and garlic mixture on top.
Add 1 ½ cups of shredded mozzarella cheese and half the Parmesan cheese and spread out evenly.
Layer on 3-4 more lasagna noodles on top of the mozzarella cheese. Now, pour on half the alfredo sauce.
Repeat the layering by following steps 6-11 again.
Once the lasagna has been put together, cover with aluminum foil and bake on 350°F for 1 hour.
Once done, remove the aluminum foil and let it rest for 10 minutes before slicing. Top with fresh parsley and serve.