In a large pot or Dutch oven, cook the sweet Italian sausage, ground beef, onion, and garlic over medium heat until well browned. Drain any excess fat.

Stir in the crushed tomatoes, tomato paste, tomato sauce, and water. Season with sugar, basil, fennel seeds, Italian seasoning, 1 teaspoon salt, pepper, and 2 tablespoons of the fresh parsley. Simmer, covered, for at least 1 1/2 hours, stirring occasionally.

Bring a large pot of lightly salted water to a boil. Cook the lasagna noodles in the boiling water for 8 to 10 minutes. Drain the noodles and rinse with cold water to prevent sticking.

In a small mixing bowl, combine the ricotta cheese with the egg, remaining 2 tablespoons of parsley, and 1/2 teaspoon of salt. Mix until smooth.

Preheat your oven to 375 degrees F (190 degrees C).

To assemble, spread 1 1/2 cups of the meat sauce in the bottom of a 9x13-inch baking dish. Arrange 6 noodles lengthwise over the meat sauce. Spread with one half of the ricotta cheese mixture. Top with a third of the mozzarella cheese slices.

Spoon another 1 1/2 cups of meat sauce over the mozzarella, and sprinkle with 1/4 cup of Parmesan cheese. Repeat the layers (noodles, ricotta, mozzarella, meat sauce, Parmesan), finishing with remaining mozzarella and Parmesan cheese.

Cover the baking dish with aluminum foil. To prevent the cheese from sticking, spray the foil with cooking spray or ensure it does not touch the cheese.

Bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 25 minutes until the cheese is bubbly and golden brown.

Let the lasagna rest for 15 minutes before slicing and serving to allow the layers to set.