In a large skillet over medium heat, add a splash of olive oil and cook the ground beef and Italian sausage until browned, about 5–7 minutes. Stir in the diced onion and minced garlic, cooking until the onion becomes translucent, roughly 3 minutes. Then, mix in the crushed tomatoes, tomato paste, sugar, dried basil, salt, and black pepper. Let the sauce simmer on low heat for 30 minutes, stirring occasionally.

While the sauce simmers, bring a large pot of salted water to a boil. Add the lasagna noodles and cook until al dente, about 8–10 minutes. Once ready, drain the noodles and toss them in a bit of olive oil to prevent sticking.

In a medium bowl, combine the ricotta cheese, egg, and a pinch of salt and pepper. Mix thoroughly until smooth and creamy.

Preheat the oven to 375°F (190°C). Spread a layer of meat sauce at the bottom of a large baking dish. Lay down three cooked noodles, followed by a third of the ricotta mixture and a sprinkle of shredded mozzarella. Repeat the layers, ending with a final layer of sauce topped with the remaining mozzarella and grated Parmesan.

Cover your lasagna with foil and place it in the preheated oven. Bake for 25 minutes, then remove the foil and continue baking for an additional 25 minutes or until the cheese is golden and bubbling.

Once baked, remove the lasagna from the oven and allow it to rest for 10-15 minutes before slicing. Garnish with fresh parsley and serve warm.