So here's the cheat. You take a metal sauce pan (preferably with a double bottom) over a small heat. Melt some butter (about the size of a walnut to make sauce for two people), then sprinkle in a roughly equivalent amount of AP flour. Stir it up until it makes a Goo, and fry until the goo starts to sizzle.

Then just dump in half a glass of cold tap water. Plus a pinch of salt.

You *will* need to start stirring it immediately and not stop. Use a metal fork or a whisk, and have everything else prepared beforehand so you do not leave this unattended. It won't burn so easily but it *will* clump if given half the chance.

Without the milk solids in the way, you can much more clearly see the mixture thicken and become creamy, at which point you take it off the heat, add whatever flavors you want (lemon or horseradish are some very good choices), heat again, and finish up with slightly less than half a glass of whatever cream you like. Sweet or sour works equally well. Cream is made by removing some of the water from milk, so you basically hold back the milk solids until the sauce is almost done and they can't ruin things for you.

That's very nice and all, you might say, but I do not really see a place in my cooking for fancy French white sauces. In which case consider this: if you add grated cheese to this mixture at the "flavor" step (of a type like Cheddar that melts easily), you will have half of the best macaroni and cheese you've ever tasted.