Cook the ground beef until there is no more pink present. Drain out any excess grease from the skillet. Season the meat with the seasoned salt, garlic powder, Italian seasoning, and black pepper. Mix it until it is all thoroughly combined.

Add the pasta sauce directly into the meat mixture and gently stir it until it is fully combined. Set the meat sauce aside and get started on the cheese. 

In a bowl, combine the ricotta cheese, 1 cup of the mozzarella cheese, the grated parmesan, the large egg, and the italian seasoning. 

Preheat the oven to 375°F. Spray a cast iron skillet or a 9x13 baking dish with non-stick cooking spray. Spread half of the meat sauce evenly over the bottom of the skillet, reserving the other half for the top. 

Use a spoon to add about one tablespoon of the cheese mixture into your jumbo pasta shells. Once the cheese is added, place them in an even layer right over the top of the meat mixture in your skillet or dish. 

Continue this process until all of the shells are filled with the cheese. Pour the rest of the meat sauce over the top of the stuffed shells. Then sprinkle the remaining mozzarella cheese evenly over the top.

Cover the dish with foil and place it in the oven. Bake the dish covered for 20 minutes. Remove the foil and bake for an additional 7-10 minutes, just until the top is bubbly and golden brown. Remove the skillet from the oven and serve immediately.