Preheat your oven to 350°F (175°C). Boil salted water in a large pot and cook lasagna noodles until al dente, then drain and rinse.

In a skillet over medium heat, sauté ground beef, Italian sausage, diced onion, and minced garlic for 5-7 minutes until browned.

Stir in pasta sauce, tomato paste, Italian seasoning, salt, and black pepper. Let it simmer for 5 minutes.

In a mixing bowl, combine the cheese filling ingredients: mozzarella, Parmesan, ricotta, parsley, beaten egg, and salt.

Spread 1 cup of meat sauce in a baking dish, layer 4 noodles, half the cheese mixture, and another cup of sauce. Repeat layers and finish with noodles and remaining sauce.

Cover with foil and bake for 45 minutes. Uncover, add remaining cheese, and bake for another 15 minutes until bubbly.

Let it rest for at least 15 minutes before serving.