Preheat your oven to 375°F (190°C).
In a skillet, cook the ground beef over medium heat until browned. Drain the fat.
Add the marinara sauce to the cooked beef, stirring until combined. Simmer for 10 minutes.
In a bowl, combine ricotta cheese, mozzarella, Parmesan, egg, salt, and pepper. Mix well.
Spread a thin layer of meat sauce in the bottom of a 13x9-inch baking dish.
Place the lasagna noodles on top of the sauce, followed by a layer of the cheese mixture, then more sauce. Repeat layers, ending with sauce on top.
Cover with aluminum foil and bake for 25 minutes. Remove foil and bake for an additional 20 minutes until bubbly and golden.
Let it rest for 10 minutes before slicing and serving.