In a large bowl, stir together the sour cream, cream of mushroom soup, half of the melted butter (1/4 cup), salt, pepper, garlic powder, onion powder, cayenne and grated cheese.
Then stir the (frozen) potatoes into this mixture.
Lightly grease a 9×13 baking pan. Add this mixture to the pan, spreading evenly.
In a gallon-sized ziplock bag, crush the corn flakes and then toss in the remaining melted butter. Sprinkle this over the potato layer.
Cover the dish in aluminum foil and bake at 350°F (177°F) for 45-50 minutes in total.
After the first 25 minutes, remove the aluminum foil for the remainder of the bake time.
When done, the top will look golden and crunchy. Sprinkle the green onions over the top before serving.
Notes
If you want to make this ahead of time, you can! Simply keep the cornflakes separate until you area ready to bake so they don’t get soggy.If you want to add more heat and flavor, I’d swap half the cheddar cheese for pepper jack cheese instead.If you are making this for Thanksgiving or Christmas, consider swapping the green onions or rosemary or thyme.