3 tbsp. butter
3 tbsp. flour
1 1/2 c. milk
1 1/4 c. grated sharp cheddar cheese, packed
1/4 tsp. salt
1/8 tsp. pepper
1 qt. cubed 3/4 inch cooked potatoes
1/3 c. fine dry bread crumbs

In a large 1 quart saucepan, over low heat, melt butter. Stir in flour. Remove from heat. Gradually stir in milk, keeping smooth. Cook, stirring constantly, over moderately low heat until thickened. Turn off heat and stir in 1 cup of the cheese until melted. Add salt and pepper.

Turn potatoes into a 2 quart square glass baking dish (8 x 8 x 2 inches). Pour sauce over potatoes and sprinkle with remaining 1/4 cup cheese and bread crumbs. Bake in a preheated 350 degree oven until bubbly hot and topping is golden, approximately 30 minutes.