Scalloped potatoes

My hubby got this recipe from 1 of his co-workers & made it on Sunday. Yes, he cooks & is really good at it. I didn't get any pics of it. It's so good.

Scalloped potatoes

6 tbls. butter
1/2 tsp, salt
4 cups, half & half
1 large onion
3 tbls, corn starch
1/2 tsp, pepper
2 lbs potatoes

Slice potatoes & onions about 1/4 inch thick. Preheat oven to 350 degrees. Grease with butter a 9x13 pan. Reserve 1 cup of half & half & mix with corn starch & set aside. Melt butter in a 3 qrt sauce pan. Remove from heat. Stir in salt & pepper & 3 cups of half & half. Slowly bring to a bowl, then add the corn starch mixture. Stir & boil for about 30 seconds. Remove from heat. Layer pan with 1/2 of the potatoes & 1/2 of the onions & 1/2 of the sauce. Then sprinkle with grated cheese. Then repeat with another layer of potatoes, onions, sauce & cheese. Bake for 1 hour or until golden brown.