Cook the mostaccioli pasta as directed on the package for al dente. After cooking, rinse it with water and let it drain.
Heat a large iron skillet over medium-high heat. Cook the ground beef in the skillet, stirring until it is completely browned. Once browned, drain off any excess fat.
To the skillet with the beef, add the spaghetti sauce, cheddar cheese soup, ground black pepper, and dried Italian herb seasoning. Stir everything together until it is well mixed.
In a large pasta pot, combine the cooked pasta, the sauce mixture from the skillet, and 2 cups of shredded mozzarella cheese.
Place the mixed ingredients back into the iron skillet.
Sprinkle the remaining 1 cup of mozzarella cheese evenly over the top of the pasta mixture.
Bake the pasta in an oven preheated to 350°F for 40 minutes, or until everything is hot throughout.