Preheat your oven to 375°F (190°C).
Cook the jumbo pasta shells according to package instructions until al dente.
In a skillet, brown the ground beef over medium heat until fully cooked.
Drain excess fat and add Italian seasoning, salt, and pepper.
In a mixing bowl, combine the cooked beef, ricotta cheese, half of the mozzarella, Parmesan cheese, and egg.
Stuff each cooked shell with the beef and cheese mixture.
Spread a thin layer of marinara sauce on the bottom of a baking dish.
Place the stuffed shells in the dish and cover with remaining marinara sauce.
Sprinkle the remaining mozzarella cheese on top.
Bake for 25-30 minutes until bubbly and golden brown.