Au Gratin Hash Brown Casserole

INGREDIENTS

1 30 ounce package

frozen shredded hash brown potatoes, (thawed)

4 tbsp

butter, (diced into 1 Tbsp pieces)

1/2 cup

finely chopped yellow onion

1/4 cup

all-purpose flour

2 3/4 cups

milk ((whole or 2%))

1 1/2 cups

shredded sharp cheddar cheese

1/2 cup

finely shredded parmesan cheese

1 cup

sour cream

Salt and freshly ground pepper

4 cups

cornflakes, (crushed (nearly 2 cups once crushed))

3 tbsp

butter, (melted)

1 1/2 tbsp

chopped fresh parsley