For the Lasagna

1. Preheat oven to 375 degrees.
2. Prepare noodles as directed on package or take this shortcut: Spread uncooked noodles in large pan (I used an aluminum roasting pan). Bring water to a boil, using a large tea kettle if you have it. Pour hot water over noodles, making sure there is plenty to cover all the noodles.  Add a little olive oil to water to help prevent sticking. Let them soak while you are preparing the filling.  Drain well when ready to use.
3. In a large bowl, combine ricotta, spinach, Parmesan, egg, parsley, salt and pepper. Spray 13x9 baking dish with cooking spray. Spread about 3/4 cup of sauce over bottom of baking dish. Place 4-5 noodles over the bottom, slightly overlapping each other. Spread half of the cheese and spinach mixture over the bottom layer of noodles. Then spread half of the cooked crumbled sausage over the cheese mixture. Top layer with about a cup of sauce. Repeat next layer the same. Top last layer with noodles and remaining tomato sauce (about 2 cups), if you made the sauce using my recipe you will have sauce leftover. You can freeze any unused sauce for future use.
4. Cover with aluminum foil and bake in 375 degree oven for 20-25 minutes. Take aluminum foil off lasagna and spread shredded mozzarella over top layer. Cook uncovered for an additional 15-20 minutes until cheese is melted and slightly browned and sauce is bubbly
5. Let pasta stand for at least 10 minutes before cutting and serving. Serve with grated Parmesan, red pepper flakes and garlic bread.

For the Tomato Sauce

1. In large saucepan, heat olive oil and add minced onion and a small pinch of salt. Saute over medium heat until onions are softened. Add both cans of tomatoes to pot. Add a small amount of water to each can and swirl to grab any leftover sauce and add to pot. Bring sauce to a simmer over medium heat. Add oregano, parsley, salt, pepper and sugar. Sugar is optional, depending on taste.
2. Continue to simmer for about 20-25 minutes. Taste for any additional salt and pepper.