Hamburger Pie

Ingredients

• 1 medium onion, chopped
• 1 lb. good ground beef
• 2 1/2 c. or 1/2 lb. cooked green beans
• 1 (10 1/2 to 11 oz.) can condensed tomato soup
• 5 medium potatoes, cooked or equivalent amount instant mashed*
• 1/2 c. warm milk
• 1 beaten egg
• salt and pepper to taste
• 1/2 c. shredded American cheese for topping (optional)