Instructions

Sauce

1. Melt butter in a small saucepan over medium-low heat.
2. Sprinkle in flour and stir until well-combined and a roux, or thick paste, forms.
3. Slowly whisk in milk and cook on low heat until mixture is creamy and slightly thickened.
4. Whisk cream into the milk mixture.
5. Set sauce aside.

Potatoes

1. Preheat oven to 400F.
2. Lay fries out in a casserole dish.
3. Pour sauce evenly over top of fries.
4. Spread a layer of sliced onions on top of sauce.
5. Generously sprinkle with salt and pepper.
6. Sprinkle cheddar cheese over the top of the onions.
7. Sprinkle with minced Italian parsley.
8. Cover dish with foil, and poke holes through the top of the foil 5 to 6 times to allow steam to escape.
9. Place casserole on the middle rack of the oven.
10. Bake for 1 hour and 15 minutes, or until the potatoes are fork-tender.
11. During the last 15 minutes of baking time, transfer the casserole to a lower rack in the oven. This ensures a brown and crispy crust on the bottom of the fries.
12. Serve hot.