Potatoes Au Gratin

(Courtesy of Kraft)

Ingredients:
1/4 c. butter or margarine
1/4 c. flour
1/2 tsp. dry mustard
1/4 tsp. pepper
2 1/2 c. milk
1 pkg. (8 oz.) shredded cheddar cheese, divided
2 Tbsp. chopped onions
6 c. thinly sliced peeled baking potatoes (6-8 potatoes)

Directions:
Heat oven to 350 degrees.

Melt butter in a medium saucepan on medium heat.  Blend in flour, mustard and pepper; cook and stir 1 minute.  Gradually add milk, stirring until well blended; cook 3-5 minutes until thickened, stirring constantly.  Add 1 1/2 c. cheese and onions; cook 2-3 minutes until cheese is melted, stirring frequently.

Layer potatoes and cheese sauce alternately in a 2 quart casserole sprayed with cooking spray, ending with cheese sauce.

Bake 1 1/4 hours or until potatoes are tender.  Sprinkle with remaining cheese; bake 5 minutes or until melted.