Preheat oven to 350-degrees.
In a large bowl, combine hash browns, 1/4 cup melted butter, cream of chicken soup, ham, sour cream, chopped onion, cheddar cheese, salt and pepper. Spray a 3 quart casserole dish with non-stick cooking spray. Place mixture in casserole. Level out.
In a medium saucepan over medium heat, saut cornflakes in 1/4 cup melted butter, and sprinkle the mixture over the top of the casserole.
Bake covered in preheated over for 50-60 minutes or until hot and bubbly. (Cooking times may vary.)