Au Gratin Potatoes

This is yet another favorite that my grandma would make. I love potatoes. I love cheese. I love butter. Fine, I just love food. This is a great dish to serve with a roast or chicken. If you'd like, you could just add chopped up ham leftovers before cooking and have a main dish as well! Either way, it's delicious.

4 potatoes sliced 1/4" slices
1 onion, sliced into rings
3 Tbsp butter
3 Tbsp flour
1/2 tsp salt
2 C. milk
1 1/2 C Cheddar, shredded

Preheat oven to 400 degrees.
Butter a 1 qt dish.
Layer potatoes, onions, potatoes.
Melt butter in sauce pan.
Whisk in flour, constantly stirring, let cook for 1 1/2 minutes.
Stir in milk, cook until thick.
Stir in cheese and cook 1-2 minutes longer.
Pour mixture over potatoes.
Cover with foil.
Bake 1 1/2 hours.