Au Gratin Potatoes

Not the healthiest thing to eat, but oh so delicious. I served it with a green salad to balance things out. This recipe is from Betty Crocker's New Cookbook, published in 1996.

6 medium boiling or baking potatoes (2 pounds)
1/4 cup butter
1 medium onion, chopped (1/2 cup)
1 tbsp all-purpose flour
1 tsp salt
1/4 tsp ground black pepper
2 cups milk
2 cups shredded sharp cheddar cheese (8 ounces)
1/4 cup fine dry bread crumbs
paprika

Heat oven to 375F. Scrub potatoes. You can peel them if you want, but the skins get very soft while baking in the cheese sauce, so I think it's unnecessary.
Cut potatoes into thin slices to measure about 4 cups.
Spread potatoes in ungreased 1 1/2-quart casserole.
Melt butter in 2-quart saucepan over medium heat. Cook onion in butter about 2 minutes, stirring occasionally, until tender. Stir in flour, salt and pepper. Cook, stirring constantly, until bubbly.
Stir in milk and 1 1/2 cups of the cheese. Heat to boiling, stirring constantly. Boil and stir 1 minute.
Pour cheese sauce over potatoes in casserole.
Bake uncovered 1 hour. Mix remaining cheese and the bread crumbs; sprinkle over potatoes. Sprinkle with paprika. Bake uncovered 15 to 20 minutes longer or until top is brown and bubbly.