Cook the pasta according to the directions on the box.
In the meantime, brown the beef in a large cast iron skillet. Season with taco seasoning mix, salt and pepper.
Add the salsa to the pan and toss to coat. Cook about 3 minutes, then add the pasta and mix.
Preheat the broiler.
Mix 1 cup of the cheese into the meat and pasta mixture. Top with the remaining cheese and broil for 2-3 minutes until the cheese is melted.
Serve hot.