In a large skillet, heat over medium heat and brown ground beef and Italian sausage for about 6–8 minutes, until no pink remains. Drain any excess fat, then add diced onion and minced garlic. Sauté until the onions are translucent, roughly 3–4 minutes. Stir in crushed tomatoes, tomato paste, sugar, dried basil, salt, and pepper. Let the sauce simmer for 30 minutes.

In a large pot, bring water to a rolling boil and add a generous pinch of salt. Carefully add lasagna noodles and cook them according to package instructions until al dente, usually 8–10 minutes. Drain carefully, then spread out the noodles on a clean surface to prevent sticking.

In a medium bowl, combine ricotta cheese with egg, half of the shredded mozzarella, and half of the grated parmesan cheese. Mix until well combined. In a greased baking dish, start layering by spreading a layer of meat sauce, followed by noodles, a third of the ricotta mixture, and more sauce. Repeat these layers until all ingredients are used, finishing with a layer of sauce and the remaining mozzarella and parmesan on top.

Preheat your oven to 375°F (190°C). Cover the prepared lasagna with foil and bake for 25 minutes. Then, remove the foil and bake for an additional 25 minutes until bubbling and golden brown on top.

Once baked, allow the classic lasagna to rest for 10-15 minutes before slicing. If desired, sprinkle with fresh parsley.