Cheesy Potato Casserole

My best friend Judi shared this recipe with me and it has become a family favorite. 1 (32 oz) package frozen hash brown potatoes, thawed 2 cups shredded cheddar cheese 1 (10.5 oz) can condensed cream of celery soup 1 (16 oz) carton sour cream 1/2 cup chopped onion 1/2...