In a large pot, bring salted water to a boil. Cook the lasagna noodles according to package instructions until al dente. Drain the noodles, and gently lay them on a clean kitchen towel to prevent sticking. Set aside.
In a large skillet set over medium heat, add the ground beef and Italian sausage. Cook, stirring occasionally, until both are well browned. Use a spoon to break up any large chunks. Once browned, drain excess fat from the skillet.
To the meat mixture, add the chopped onion and minced garlic. Sauté for about 3-5 minutes, or until the onion becomes translucent and fragrant.
Stir in the crushed tomatoes, tomato paste, dried oregano, dried basil, salt, and pepper. Bring the mixture to a gentle simmer, allowing the flavors to meld together. Let it simmer uncovered for about 20 minutes, stirring occasionally.
In a separate mixing bowl, combine the ricotta cheese, the egg, a pinch of salt, and a dash of pepper. Mix until the mixture is smooth and well-blended.
In a 9x13 inch baking dish, spread a thin layer of the meat sauce across the bottom. Place 4 layers of lasagna noodles on top, followed by half of the ricotta mixture, one-third of the meat sauce, and a sprinkle of mozzarella cheese. Repeat this layering process once more. Finish with a final layer of noodles, the remaining meat sauce, the rest of the mozzarella cheese, and a generous sprinkle of Parmesan cheese.
Preheat the oven to 375°F (190°C). Cover the baking dish with aluminum foil, making sure the foil does not touch the cheese. Bake for 25 minutes. After this time, remove the foil and continue baking for an additional 25 minutes, until the cheese is melted, bubbling, and golden on top.
Once baked, allow the lasagna to cool for 10-15 minutes before slicing. Just before serving, garnish generously with fresh basil leaves.
Notes
Allow the lasagna to cool before slicing for better layer stability.