2 tbsp. butter
2 tbsp. flour
1 tsp. salt
Dash pepper
1 1/2 c. warm milk
1 lb. potatoes, pared and thinly sliced (about 3 med.)
2 tbsp. finely chopped onion
1 tsp. butter

Heat oven to 350 degrees. Melt 2 tablespoon butter over low heat, stir in flour and seasonings. Cook over low heat, stirring until smooth and bubbly. Remove from heat. Stir in milk. Heat to boiling, stirring constantly. In greased 1 quart casserole, layer half the potatoes, all the onion and half the sauce. Top with remaining potatoes and sauce. Dot with 1 teaspoon butter. Cover and bake 30 minutes. Uncover and bake until potatoes are tender, about 35 minutes.