Mom'S Scalloped Potatoes - cooking recipe

Ingredients

2 lbs potatoes
3 tablespoons butter
3 tablespoons flour
2 1/2 cups milk
1/4 cup onion

Preparation

Thinly slice potatoes, cover with cold water and set aside.
In medium saucepan, melt butter. Stir in flour until no lumps remain, add milk and whisk until combined.
Cook milk and flour mixture until thick enough to coat the back of a spoon.
Grease a 2 qt casserole dish.
layer 1/3 sliced potatoes.
1/2 of onion.
1/3 white sauce.
Repeat layers, finishing up with potatoes and sauce.
Dot with butter.
Cover and bake 30 minutes at 350 degrees.
Uncover and back an additional 1 hour.