Au Gratin Potatoes (weight watchers)

Au Gratin Potatoes (WW)
mom2brs via weightwatchers

Ingredients:
1 spray of cooking spray
1 tbsp salted butter
1 medium uncooked onion, diced
2 tbsp all purpose flour
2 cups fat free skim milk
2 lbs uncooked Yukon potatoes, thinly sliced
1 cup low fat shredded cheddar cheese
Salt & Pepper

Directions:

Preheat oven to 375°F. Coat a 2-quart covered baking dish with cooking spray.

Melt butter in a large pot over medium heat. Add onion and cook, stirring occasionally, until onion begins to brown, about 5 minutes. Stir in flour; add milk slowly, stirring. Add potatoes and stir to mix. Bring to a boil. Stir in 3/4 cup of cheese, salt and pepper.

Pour mixture into prepared baking dish and level out surface. Bake for 1 hour, uncovered. Cover and bake until potatoes are fork-tender, about 20 minutes more.

Change oven temperature to broil. Sprinkle remaining cheese over potatoes. Broil 6 inches from the heating element until the cheese is golden brown, about 1 to 2 minutes. Allow to cool for 5 minutes before serving.