If you are in the USA, I found something that may help - from the copyright office. Apparently, a recipe that simply lists ingredients does not fall under copyright laws so you could not stop someone from using it.
"Copyright protection may, however, extend to substantial literary expression—a description, explanation, or illustration, for example—that accompanies a recipe or formula or to a combination of recipes, as in a cookbook."
IM DYING OF LAUGHTER BECAUSE I KEEP LOOKING AT YOUR QUESTION AND THEN YOUR PROFILE PICTURE OH MY GOD XD oh and btw you can tell them that the recipe their using is your fake one, and that you're actually hiding your real one. Hope that helped. :P
4 months ago
Last edited at 1:06PM on 12/22/2013
Since I don't know how they got the recipe the only thing I can think of is pretend as though you don't care if they use your recipe or not. Write up a variation of the original, but change up a couple of the ingredients and tell them they have the wrong recipe then give them the altered one. Just explain that you forgot to add something to the first one.
Or ask them nicely not to use it. Is it copyrighted by any chance? If not, I don't see how you can stop them.
Isn't this the season of giving? But seriously. Your recipe? Come on. How many hundreds of thousands of recipes are out there. You mean NO one has done it this way before? Famous Amos is probably rolling around in his grave right now doubled over with laughter. Merry Christmas.