Heat a large pot of water to boiling, add pasta and cook for 5 - 6 minutes, al dente. (it will continue to cook in the oven)
3/4 lb Thin Spaghetti
Drain the pasta and let it cool.
Preheat your oven to 350°F. Grease a 9x13 baking dish with cooking spray.
In a large sauté pan. Turn the heat on, to medium. Slowly cook the sausage, breaking it up into smaller pieces. Cook until the sausage is cooked through, no longer pink anywhere, and lightly browned. Remove the sausage from the pan to a paper towel-lined dish.
1 lb Italian sausage
Drain most of the fat from the pan
Add the chopped onions to the pan. Increase the heat to medium-high. Cook, stirring frequently until the onions become translucent. Add the minced garlic and red chili pepper flakes, and cook a minute more.
1 medium onion, chopped (about 1 1/2 cups), 2 cloves Garlic, 1/2 teaspoon Red Pepper flakes
Add the marinara sauce and water to the pan with the onions. Add the sausage back, Italian seasoning, and chopped parsley. Bring to a simmer and reduce the heat to a very low simmer. Cook for 10 to 15 minutes, while you prepare the pasta. Season to taste with salt and pepper.
3 cups or 24 ounces of Marinara, 1 cup water, 1 Tbsp Italian seasoning, 1/2 cup Fresh Parsley, chopped
Place the cooled pasta in a large bowl. Toss with olive oil, then 2 beaten eggs.
1 Tbsp Olive Oil, 2 large eggs, beaten
Place half of the pasta in an even layer in the casserole dish.
Cover with half of the sauce. Then dot the sauce with half of the ricotta cheese. Sprinkle half of the parmesan over the ricotta layer and then half of the mozzarella. Layer again with the remaining pasta, sauce, parmesan, and mozzarella.
1 cup Parmesan cheese, grated, 1 1/2 cups Ricotta Cheese, 3 cups Mozzarella Cheese, shredded
Cover with foil and bake for 40 min at 350°F. Remove the foil and bake an additional 20 minutes uncovered.
Remove from oven and let rest for at least 10 minutes before cutting into squares and serving.