2 pounds potatoes (about 6 medium)
3 tablespoons butter or margarine
3 tablespoons flour
Salt and pepper
2 1/2 cups milk
1/4 cup finely chopped onion
1 tablespoon butter or margarine
Preheat oven to 350 degrees F.
Wash potatoes; pare thinly and remove eyes. Cut potatoes into thin slices to measure about 4 cups.
Melt 3 tbsp butter in saucepan over low heat. Blend in flour and seasonings. Cook over low heat, stirring until mixture is smooth and bubbly. Remove from heat. Stir in milk. Heat to boiling, stirring constantly. Boil and stir one minute.
In greased 2-quart casserole, arrange potatoes in 2 layers, topping each with half the onion and 1/3 of the white sauce. Top with remaining potatoes and sauce. Dot with 1 tablespoon butter. Cover, bake 30 minutes.
Uncover, bake 60 to 70 minutes longer or until potatoes are tender. Let stand 5 to 10 minutes before serving.