Crock Pot Scalloped Potatoes

I wanted to make scalloped potatoes but I wanted them to cook while I was at church. So this is what I did. Everyone liked them!

Crock Pot Scalloped Potatoes
Spray crock pot. Layer in crock pot:
6 large peeled & sliced potatoes
1 grated onion or dry onion flakes
1 1/2 c. grated cheddar cheese
1/2 c. Parmesan Cheese
Make Sauce:
Melt 1/4 c. butter
Add:
1/4 c. flour
3/4 to 1 c. milk
1 t. salt
1/2 t. pepper
Stir, heat slightly in microwave and pour over potatoes.
Cook on high 3 to 4 hours until cooked through.