Prepare macaroni and cheese according to package directions. Meanwhile, in cast iron skillet, cook beef until no longer pink; drain. Stir in salsa and taco seasoning; remove from skillet and set aside. Wipe out skillet and spay with cooking spray. Spread macaroni into the prepared cast iron skillet. Layer with beef mixture, sprinkle with cheese.

Bake, uncovered, at 350° for 15-20 minutes or until heated through. Serve with sour cream, chopped tomatoes, and onions if desired. Yield: 8 servings.