Preheat your oven to 375°F (190°C).
Boil the lasagna noodles according to package instructions; drain and set aside.
In a large skillet, brown the ground beef over medium heat until fully cooked; drain excess fat.
Add marinara sauce to the beef; simmer for 10 minutes.
In a separate bowl, mix ricotta cheese, egg, Italian seasoning, salt, and pepper.
Spread a layer of the meat sauce at the bottom of a baking dish.
Place a layer of noodles over the sauce, followed by a layer of the ricotta mixture.
Add a layer of mozzarella cheese, then more meat sauce.
Repeat the layering process until all ingredients are used, ending with mozzarella on top.
Bake for 45 minutes, or until the cheese is bubbly and golden brown.