Au Gratin Potatoes

I *think* this was a Weight Watchers recipe that I've played with and made my own. These are sooooo good and sooooo cheesy, but a lot lighter than traditional Au Gratin Potatoes!

Au Gratin Potatoes
6 servings

Ingredients:
2lbs russet potatoes scrubbed and sliced thin (I use a mandolin)
1 onion sliced thin
1 tbsp butter
2 tbsp flour
2 cups skim milk
1 1/4 cup low fat cheddar, shredded
1/4 cup grated Parmesan

Directions:
1. Preheat oven to 375. Coat a 2-3 qt covered casserole dish with cooking spray. Melt butter in a large pot. Add onion and cook, until onion begins to soften. Stir in flour and cook for 2 minutes.


2. Slowly add in milk whisking constantly, removing any lumps. Add potatoes, stir to coat and bring to a boil.  Remove from heat and add in salt, pepper and one cup of cheddar. Mix well. Pour mixture into prepared dish and cook, uncovered for one hour.

3. Cover potatoes and bake for another 20 minutes or until potatoes are tender. Sprinkle Parmesan and remaining cheddar on top and broil until cheese is melted and slightly brown. Remove from the oven, let sit for 5-10 minutes and enjoy!