Found this recipe at: http://www.epicconstructions.com/mirror/mcd/ The recipes are in pdf & various fonts & formatting that don't translate well when printed. Some of the words I can't even read on paper at all (2 point type size), so I'm posting it here so we can use it again. It's the closest to McDonald's we've found to date. We had a package of the original sauce to compare side-by-side with. There is definitely no cayenne in the original (which is one of the clone's best assets) & the original tastes like it has a touch of BBQ sauce in it. I've seen a lot of recipes with Heinz 57 listed but I wasn't interested in trying another one of those tonight. This recipe utilized everything I already had on hand. We let it refrigerate for about 6 hours & the flavors mellowed quite a bit but I think the sauce will benefit from a longer refrigeration time as the mustard & vinegar flavors are overpowering right after mixing.