This sauce is spectacular! It's not easy, but it is GOOD. We have a bay tree growing as a house plant so I used a fresh bay leaf (one whole). I also took the rare (for me) step of weighing the ingredients. I usually don't like cheese sauces, but this one was great. I used it to make Hot Browns, hint hint, nudge nudge.
this is indeed the traditional french sauce. i added some catenne and served it over a combo of asparagus, red pepper, petit green beans and baby carrots, sauteed. excellent side dish to chicken