In a large skillet, brown your chosen meat; drain excess fat, then add onion and garlic and cook until softened. Stir in crushed tomatoes, tomato paste, oregano, basil, salt, and pepper, then simmer the sauce for at least 30 minutes to allow flavors to meld.

In a medium bowl, combine ricotta cheese, Parmesan cheese, and egg; mix thoroughly and set aside. If using traditional lasagna noodles, boil them according to package directions until al dente, then drain and rinse with cold water to prevent sticking.

Spread a thin layer of meat sauce over the bottom of a 9x13 inch baking dish. Arrange a single layer of lasagna noodles over the sauce, trimming if necessary to fit the dish.

Spread half of the ricotta cheese mixture over the noodles, then sprinkle with a generous portion of shredded mozzarella. Top this with another layer of meat sauce, ensuring an even spread, and then add another layer of noodles.

Repeat the cheese and sauce layers, alternating with noodles, until all ingredients are used, ending with a final layer of meat sauce. Sprinkle the remaining mozzarella cheese evenly over the top layer of sauce.

Cover the baking dish tightly with aluminum foil and bake in a preheated 375°F (190°C) oven for 25 minutes. Then, remove the foil and continue baking for an additional 20-25 minutes, or until the top is golden brown and bubbly.

Once baked, remove the lasagna from the oven and let it rest for 10-15 minutes before slicing and serving. This resting period allows the layers to set, making it easier to cut and ensuring it holds its shape beautifully.