2Stir cream cheese, cream of celery soup, sour cream, and Cheddar cheese in a large bowl until thoroughly combined. Gently fold hash brown potatoes into soup mixture. Stir corn flakes with melted butter in a separate bowl. Spread potato mixture in an even layer into a 9x13-inch baking dish; sprinkle buttered corn flakes over the top.
3Bake until casserole is bubbling and topping has browned, about 1 hour.