Preheat your oven to 375°F degrees and lightly grease a 9x13 baking dish.
Combine the ricotta cheese and the egg in a mixing bowl. Mix to combine.
Brown the Italian sausage in a large skillet.
Add the onion and garlic, and cook until tender.
Pour the crushed tomatoes, tomato paste, and tomato sauce into the skillet. If the mixture ends up too thick, add a splash of water to dilute it.
Add sugar, parsley, salt, and black pepper. Let it simmer for 30 minutes, stirring now and then.
Cook the noodles according to the package instructions.
Create the first layer by spreading ⅓ of the meat sauce, ⅓ of the noodles, and ⅓ of the ricotta mixture.
Repeat until you’re out of ingredients.
Top the baking dish with mozzarella cheese and parmesan cheese.
Bake, covered, for 25 minutes.
Remove the cover and bake again uncovered for another 25 minutes.