It looks like another cookbook has been published which contains recipes copied from the MedievalCookery website, so I thought I'd take some time to clear up some potential confusion over the internet as a whole, recipes, and copyright.
First let me point out that just because something is freely available on the internet does not mean that you copy it and use it as you will. For example, I have a recipe online called Tostee.
It's a nice little recipe, and while it didn't take me too long to work out, it's still my work. I place a certain amount of value on my work, even the small stuff, and therefore would like to receive compensation and credit whenever it's reproduced. To remind people of this I even added this bit at the bottom of the web page:
Now here's the interesting part. There are portions of this recipe that actually could be used without permission. For example, the page contains the original source of the recipe, which is a manuscript from the fourteenth century.
That original manuscript is in the public domain. You can copy and paste and publish it to your heart's content and nobody's lawyers will send you a nastygram about it. You can even read through it and work out a modern version of the recipe ... which is exactly what I did. If I found out someone else did that I'd say, "Good job! Do another one!" Really. I'm quite enthusiastic about people working out modern versions of medieval recipes.
The tricky part is the chunk of the recipe above that.
That part of the recipe is my original work. If you use that part in your cookbook without permission then I'll be rather cranky, especially since I don't make it all that difficult to actually get permission.
Oh, and if you use that part without permission and change a word or two, that still counts as copyright infringement and I'll still get cranky.
There is one weird bit to copyright law however, and that has to do with this bit of the recipe:
Technically, a simple list of ingredients cannot be copyrighted, so you might be able to get away with using this part as well. However, the wording of the individual items and the order they're given in is still covered by copyright law, so it's really not a good idea to use it without permission either.
So remember: if you want to use something from someone's website, ask first! If they're like me then the odds are pretty good they'll let you.