1/4 c. chopped onion
1/4 c. butter
1/4 c. flour
2 1/2 c. milk
5 c. potatoes, peeled and thinly sliced
1 tsp. salt
1/8 tsp. pepper
3/4 c. grated cheese (Cheddar or American)

Cook onion in butter until tender. Stir in flour, salt and pepper. Add milk. Cook and stir until sauce is thickened and bubbly. Cook. Stir 1 to 2 minutes more. Remove from heat. Place half of sliced potatoes into a greased 2 quart casserole. Cover with half of the sauce. Repeat layers. Bake, covered at 350 degrees 45 minutes, stirring once. Uncover, bake about 30 minutes more or until potatoes are tender. Serves 4 to 6.