1In 12-inch skillet, cook beef and onion over medium-high heat 5 to 7 minutes, stirring frequently, until thoroughly cooked. Drain.
2Add frozen potatoes. Cook 8 to 10 minutes, stirring frequently, until potatoes are tender. Add soup and mushrooms; cook and stir until mixture is hot.
3Top with cheese. Cover; cook about 2 minutes or until cheese is melted. Sprinkle with parsley.