In a large skillet, over medium heat, brown the ground beef and Italian sausage until fully cooked, about 5–7 minutes. Drain any excess fat, then add diced onion and minced garlic. Sauté until the onion is translucent, about 3–4 minutes.

Stir in crushed tomatoes, tomato paste, sugar, dried basil, salt, and pepper. Let it simmer on low for 30 minutes, stirring occasionally.

In a mixing bowl, combine ricotta cheese, egg, shredded mozzarella, and half of the grated Parmesan. Mix with a fork until smooth and creamy.

Preheat your oven to 375°F (190°C). In a 9x13 inch baking dish, spread a thin layer of meat sauce, then place lasagna noodles over it.

Spoon in half of the ricotta mixture, followed by another layer of meat sauce and a sprinkle of mozzarella cheese. Repeat layers until all ingredients are used, finishing with meat sauce, mozzarella, and Parmesan cheese on top.

Cover with aluminum foil and bake for 25 minutes. Remove the foil and continue baking for another 25 minutes or until cheese is bubbly and golden.

Let the lasagna rest for 10–15 minutes before serving. Garnish with fresh parsley if desired.