cheesy hash brown potato casserole

Ingredients

• 1 - (2-lb) bag frozen hash brown potatoes
• 1/2 cup butter, melted
• 1 tablespoon salt
• 1 teaspoon pepper
• 1 cup onion, chopped
• 1 can cream of chicken (or celery) soup
• 1 cup sour cream
• 1 cup milk
• 4 - slices cooked bacon, crumbled
• 2 cups sharp cheese (colby or cheddar), grated
• TOPPING
• 2 tablespoons butter or margarine
• 1 cup breadcrumbs