Preheat oven to 375°F (190°C).

Cook jumbo pasta shells according to package instructions until al dente. Drain and cool slightly.

In a skillet over medium heat, cook ground beef until browned and cooked through. Drain excess fat and season with Italian seasoning. Remove from heat and cool slightly.

In a bowl, combine ricotta, cooked beef, egg, and half the Parmesan cheese. Mix well.

Spread a thin layer of marinara sauce on the bottom of a baking dish.

Stuff each pasta shell with the beef and ricotta mixture; arrange in the baking dish.

Pour remaining marinara sauce over the shells.

Sprinkle mozzarella and remaining Parmesan evenly on top.

Cover with foil and bake for 25 minutes. Remove foil and bake an additional 10 minutes until cheese is melted and bubbly.

Let cool a few minutes before serving.