Wash and slice (1/4 inch thick):

   - 8 potatoes

Slice into rings:

   - 1 onion

Grate:

   - 2 cups cheese

Preheat oven to 400° and grease a 9x13 dish.

Make a white sauce with:

   - 6 Tbs butter

   - 6 Tbs flour

   - 1 tsp salt

   - 1 1/2 cups milk

   - 1 1/2 cups water

Add the cheese to the white sauce.

Layer everything:

   1. 1/2 of the potatoes

   2. Season with salt and pepper

   3. All of the onions

   4. The rest of the potatoes

   5. Season again with salt and pepper

   6. All of the white sauce

Cover with foil and bake until the sauce bubbles and the potatoes are tender. Start checking after 45 minutes, but it may take twice that long depending on the thickness of the potatoes.