2 tablespoons butter 
3 tablespoons all-purpose flour 
1 teaspoon salt 
1/4 teaspoon pepper 
1-1/2 cups fat-free milk 
1/2 cup shredded reduced-fat cheddar cheese 
2 pounds red potatoes, peeled and thinly sliced (about 4 cups) 
1 cup thinly sliced onions, divided
1. Preheat oven to 350°. In a small saucepan, melt butter; 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; stir in cheese until melted. 
2. Coat an 8-in. square baking dish with cooking spray. Place half of the potatoes in dish; layer with 1/2 cup onion and half of the cheese sauce. Repeat layers. 
3. Bake, covered, 50 minutes. Uncover; bake until bubbly and potatoes are tender, 10 to 15 minutes longer.
TOTAL TIME: Prep: 25 min. Bake: 1 hour 
YIELD: 6 servings. 
Nutrition Facts
3/4 cup: 215 calories, 6g fat (4g saturated fat), 18mg cholesterol, 523mg sodium, 32g carbohydrate (5g sugars, 3g fiber), 8g protein. Diabetic Exchanges: 2 starch, 1 fat.