I think these are the best scalloped potatoes I have made. It is so easy to make the simple sauce. This recipe is a favorite of my friends and family. I hope you love it too.
Heat 3 tablespoons of butter in a saucepan over low heat until melted. Blend in flour, salt and pepper. Cook over low heat, stirring constantly, until mixture is smooth and bubbly. Gradually stir in milk, 1/2 cup at a time. Heat to boiling. Boil and stir 1 minute.
Arrange potatoes in greased 2 quart casserole in 3 layers, topping each layer with part of the chopped onions and 1/3 of the sauce. Dot the top with the remaining 1 tablespoon of butter, broken into little pieces.
Cover and bake at 375ºF until potatoes are tender, about 60-70 minutes. Let stand 5 to 10 minutes before serving.
Notes
Add 6 slices of cooked and crumbled bacon to the top of the scalloped potato recipe. Bake until about 15 minutes away from being perfectly cooked. Then top the casserole with 3/4 cup of grated cheddar cheese too if you like. Then bake for a final 15 minutes.
Add 1/2 to 3/4 cup grated cheddar cheese to the sauce and mix to melt. Sprinkle bread crumbs on the top if the potato mixture before baking and bake as above. Easy au gratin potatoes!