Cheesy Potato Bake - With beef

2 1/2 lbs potatoes , peeled and sliced thin 1 medium onion , diced 2 -3 cups cooked chicken, diced (or other leftover cooked meat) 2 cups cheddar cheese ,[...]

1 lb ground beef , cooked and drained 2 (4 ounce) cans mushroom stems and pieces , drained (optional) 2 (5 3/4 ounce) packages au gratin potato mix 4 cups[...]

2 lbs frozen hash browns 1 can cream of celery soup 1/2 cup chopped onion 1 cup sour cream 1/2 cup butter 2 cups shredded cheddar cheese 1 Mix together all[...]