Shepherd's Pie

In a large skillet, brown ground beef with onion and season to taste with salt and pepper. Drain fat, if any. Add soup to beef and onions. In a 9x13 inch oven proof casserole dish, layer the beef mixture first in the bottom and then the green beans. Top with mashed potatoes to make a crust, similar to a top pie crust. Sprinkle with cheese. Bake, uncovered, at 350 for 15 to 30 minutes, or until hot and bubbly and cheese is melted. NOTES : This recipe is a great one to use when taking a meal in to someone, or for families who are on split schedules, because it reheats beautifully, as well as freezes beautifully. My mother used to use it as a 'company' meal, whenever my grandparents came to visit.