Boil the jumbo pasta shells according to package instructions until al dente. Drain and set aside to cool slightly.
In a large skillet over medium heat, cook the ground beef and Italian sausage until browned and cooked through. Drain excess fat.
In a bowl, combine the cooked meat mixture with ricotta cheese, egg, garlic powder, onion powder, Italian seasoning, salt, and pepper. Mix until fully combined.
Carefully fill each pasta shell with the meat and cheese mixture. Set aside.
In a baking dish, pour a thin layer of marinara sauce at the bottom to prevent sticking. Arrange the stuffed shells on top and cover them with the remaining marinara sauce.
Sprinkle shredded mozzarella cheese evenly over the shells.
Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Remove from the oven, let it cool for a few minutes, then garnish with chopped fresh basil or parsley before serving.
Notes
Feel free to add more herbs or spices to the filling for extra flavor.