In a large skillet, heat a drizzle of olive oil over medium heat. Add ground beef and Italian sausage, cooking until browned, about 8–10 minutes. Stir in diced onion and minced garlic, cooking until translucent, about 5 minutes. Add 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 meat sauce simmers, bring a large pot of salted water to a boil. Once boiling, add cooked and drained lasagna noodles and cook until al dente, about 8–10 minutes. Drain the noodles and lay them flat on a clean kitchen towel.

In a mixing bowl, combine ricotta cheese, egg, 2 cups of shredded mozzarella cheese, and half of grated Parmesan cheese. Mix until smooth.

Preheat your oven to 375°F (190°C). In a greased baking dish, layer meat sauce, noodles, ricotta filling, and sprinkle more mozzarella cheese. Repeat layering two more times, finishing with meat sauce topped with remaining mozzarella and Parmesan.

Cover the dish with aluminum foil and bake for 25 minutes. Remove foil and bake for an additional 25 minutes until edges bubble and cheese is golden-brown.

Let the lasagna rest for 10-15 minutes before slicing. Garnish with fresh parsley before serving.