Hamburger Pie-

Hamburger Pie- ingredients- 1-recipe Mashed Potatoes or one 24-ounce package refrigerated mashed potatoes 1-1/4-pounds lean ground beef 1/2-cup chopped onion (1 medium) 1/4-teaspoon salt Dash black pepper 2-1/2-cups frozen cut green beans, thawed 1 10.75-ounce can condensed tomato soup 1/2-cup shredded process American cheese (2 ounces)