Preheat your oven to 375°F (190°C).
Cook the lasagna noodles according to the package instructions; drain and set aside.
In a skillet, brown the ground beef over medium heat until fully cooked.
Add marinara sauce to the beef, stirring well to combine.
In a bowl, mix ricotta cheese, egg, Italian seasoning, salt, and pepper until smooth.
Spread a thin layer of meat sauce in a baking dish.
Layer 3 lasagna noodles over the sauce.
Add half of the ricotta mixture over the noodles, followed by a third of the mozzarella.
Repeat the layering process: meat sauce, noodles, ricotta, and mozzarella.
Finish with a final layer of noodles, remaining meat sauce, mozzarella, and Parmesan cheese.
Cover with foil and bake for 25 minutes.
Remove the foil and bake for an additional 15 minutes until bubbly and golden.