Thanksgiving is right around the corner!

2 tablespoons of butter
3 tablespoons of all-purpose flour
1 teaspoon salt
1/4 teaspoon pepper
1-1/2 cups fat-free milk
1/2 cup shredded cheddar cheese
2 pounds red potatoes, thinly sliced (about 4 cups)
1 cup onions

Preheat oven to 350 degrees. In a small saucepan, melt the butter and then stir in flour, salt and pepper until smooth. Gradually whisk in milk. Bring to a boil, stirring constantly; cook and stir until thickened, about 2 minutes. Remove from heat and stir in cheese until melted. Spray an 8 inch baking dish with cooking spray and start layering the the potatoes in the dish. Add onions and half of the cheese sauce; repeat layers. Bake covered for 50 minutes. After 50 minutes, uncover and bake for another 10 -15 minutes or until bubbly and potatoes are tender.