Creamy Ranch Potato Casserole

6 medium russet potatoes, peeled and cubed
1 cup sour cream
1 cup ranch dressing
1 cup shredded cheddar cheese
1/2 cup chopped green onions
1/2 cup cooked and crumbled bacon
Salt and pepper to taste
2 tablespoons butter, melted
1/2 cup crushed cornflakes or breadcrumbs (optional)

Directions