Scalloped Sausage and Hash Brown Casserole

Everyone at Sunday school seemed to think this is a keeper! I just kind of made it using ingredients I had on hand. If you can think of better name for it, let me know!
I put this together Saturday night, covered it with foil and stuck it in the fridge. This morning, I just popped it into the cold oven and turned the oven on 350 degrees. It's never a good idea to place a very cold pan into a hot oven, especially glass or stoneware, as the pan can crack or shatter from the extremes of the two temperatures.

Scalloped Sausage and Hash Brown Casserole

Scalloped Sausage and Hash Brown Casserole

Casserole ingredients:

1 pound pork sausage
1/2 stick butter
1 cup chopped onions
3 tablespoons flour
2 cups half-and-half or milk
1 pt. sour cream
2 cups shredded cheddar cheese
2 lbs. frozen hash browns, Southern style (thawed)
1 tsp. salt, maybe a bit more
1/2 tsp. pepper

Topping:

2 cups crushed corn flakes combined with 1/2 stick of melted butter

Preheat oven to 350 degrees.
Coat a 9X13 baking dish with cooking spray.
Brown sausage; drain.
Saute onions in butter. When onions are tender, add 3 tablespoons of flour. Whisk until a smooth paste forms. Gradually whisk in 2 cups of half-and-half or milk. Stir continuously until thickened.
Combine white sauce with all other casserole ingredients. Cover with foil. Bake for about 45 minutes. Remove from oven, uncover and sprinkle with topping mixture. Return to oven for about 15 minutes or until topping is golden brown.