Preheat oven to 375 degrees Fahrenheit. Grease a 9x13-inch casserole dish with cooking spray and set aside. Remove ricotta cheese from refrigerator and allow to rest at room temperature. This will make it easier to spread!
Cook the spaghetti in the boiling water, following package directions until al dente. Do not overcook. Drain spaghetti and set aside. You can toss the cooked spaghetti in olive oil to keep it from clumping.
In a large skillet, brown ground beef or Italian sausage over medium heat, breaking it apart with a wooden spoon as it cooks. If there is a lot of grease, drain the meat on a paper-towel lined plate, then return to the skillet. Add the chopped onion to the crumbled meat and cook for 2-3 minutes until soft and translucent. Add minced garlic and sauté for 1 minute more.
Pour in the crushed tomatoes, tomato sauce, and heavy cream. Add Italian seasoning, salt, and pepper. Stir well to combine. Allow the sauce to simmer for about 5-10 minutes, letting the flavors meld together.
Add the cooked spaghetti to the skillet with the creamy sausage mixture. Toss everything together with tongs until the spaghetti is evenly coated with the creamy sauce
Transfer half of the spaghetti mixture to the prepared baking dish. Layer half of the mozzarella, ricotta, and Parmesan cheeses in an even layer over the spaghetti.
Add the remaining spaghetti on top of the cheese layer. Pour the rest of the sauce as well. Evenly spread or sprinkle the remaining mozzarella, ricotta, and Parmesan cheeses over the top.
Bake in preheated oven for about 25-30 minutes, or until the cheesy top layer is melted and bubbly, and the edges are golden brown.
Remove from the oven and let it cool for a few minutes. Garnish with fresh basil or parsley if desired. Slice and serve warm.
Notes
This recipe makes a heaping amount of spaghetti! It will fill your 9x13'' casserole pan. If you have a larger pan, use it! To save time, use jarred pasta sauce! You will need about 3 jars of sauce to substitute for the canned tomatoes and seasonings in the recipe above.