Scalloped Potatoes - cooking recipe

Ingredients

4 -5 medium idaho potatoes, sliced about 1/8 to 1/4 inch thick
1 medium onion, diced
1/2 cup butter
3 tablespoons flour
salt
pepper
1 can condensed cream of mushroom soup

Preparation

Place one layer of sliced potatoes on bottom of 9 x 13 inch casserole dish.
Cut butter into pieces and dot potatoes with 1/3 of butter.
Top with 1/3 diced onion evenly distributed.
Sprinkle with 1 tablespoon of flour, salt and pepper.
Repeat two more times for a total of 3 layers.
Top with can of condensed (undiluted) cream of mushroom soup, spread evenly.
Cover and cook at 350\u00b0 for 45 minutes to 1 hour.