Scalloped Potatoes
["2 lb. potatoes", "2 Tbsp. butter", "3 Tbsp. flour", "1 tsp. salt", "1/4 tsp. pepper", "2 1/2 c. milk", "1 small onion, finely chopped (about 1/4 c.)", "1 Tbsp. butter"]
["Peel potatoes and cut into thin slices, enough to measure 4 cups.", "Heat 3 tablespoons butter in saucepan over low heat.", "Blend in flour, salt and pepper.", "Cook, stirring constantly, until smooth and bubbly; remove from heat.", "Stir in milk.", "Heat to boiling, stirring constantly.", "Boil and stir 1 minute."]
["potatoes", "butter", "flour", "salt", "pepper", "milk", "onion", "butter"]