Au gratin potatoes

1. Heat the oven to 375º. Spray the casserole with cooking spray.

2. Scrub the potatoes thoroughly with a vegetable brush.

3. Peel the onion, and chop into very small pieces. Melt the margarine in the saucepan over medium heat. Cook the onion in the margarine about 2 minutes, stirring occasionally, until softened. Stir in the flour, salt and pepper. Cook 1 to 2 minutes, stirring constantly, until smooth and bubbly. Remove the saucepan from the heat.

4. Stir in the milk. Heat to boiling over medium heat, stirring constantly. Continue boiling 1 minute, stirring constantly. Remove the saucepan from the heat. Stir in 1-1/2 cups of the cheese until it is melted.

5. Peel the potatoes if you like, but peeling is not necessary. Cut the potatoes into enough thin slices to measure about 6 cups. Spread half the slices in the sprayed casserole. Pour half the sauce over the potatoes. Repeat with the remaining potatoes and sauce.

6. Bake uncovered 1 hour. Remove the casserole from the oven. Sprinkle with the bread crumbs and remaining 1/2 cup cheese. Bake uncovered about 10 minutes longer or until cheese is melted and potatoes are tender when pierced with a fork. Let stand 5 minutes before serving.