This sauce is excellent for making au gratin potatoes OR mac and cheese. My Sister is a great cook. She raised five kids on a budget and some of her recipes are really simple, easy, and dare I say "cheap"?
I like that her au gratin potatoes are excellent with this and that her kids raved about her mac and cheese made with the SAME sauce!!
Warm the milk, add the butter and melt, bring to slow boil and slowly add the slices of American cheese. (Salt and pepper to taste.)
Whisk the milk and cheese mixture and continue cooking until it makes a thick pourable sauce. If you need to thicken it more, combine a little cold milk with a tablespoon of corn starch and then add to sauce and cook for 1 or 2 minutes until thickened.
For au gratin potatoes: Slice 5 lbs unpeeled potatoes and par boil them in salted water until about half done (they will finish cooking in the oven). Pour the thickened sauce on the potatoes and stir -- Bake 350 F for 30 minutes, or until potatoes are fork tender
ALTERNATIVES for au gratin potatoes: Susan said she sometimes puts in a little cubed ham or deli ham cut in small pieces, and if she does, she also changes the sauce to be 3/4 C milk and 3/4 C chicken broth with everything else the same.
For Mac and cheese: Prepare your pasta of choice, and pour the sauce on. You're done. (Her kids rave about her mac and cheese.)