Preheat your oven to 375°F (190°C). Cook the lasagna noodles according to package directions until al dente, then drain and set aside.

In a large skillet, brown the ground beef over medium heat. Drain any excess grease and stir in the marinara sauce, simmering for 10 minutes.

In a medium bowl, combine the ricotta cheese, egg, salt, and pepper.

Spread a thin layer of meat sauce on the bottom of a 9x13 inch baking dish. Arrange three lasagna noodles over the sauce, slightly overlapping.

Spread half of the ricotta cheese mixture over the noodles, then top with one-third of the mozzarella cheese and another layer of meat sauce.

Repeat the noodle, ricotta, mozzarella, and meat sauce layers once more.

Place the final three noodles on top, cover with the remaining meat sauce, and sprinkle with the remaining mozzarella and Parmesan cheese.

Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and lightly browned.

Let the lasagna cool for 10-15 minutes before slicing and serving.