A recipe cannot be copyrighted however a cookbook can be. You can still use a recipe out of a cookbook, but if too many recipes out of one cookbook are used, the copyright could be infringed. In practical terms this means that if there is any doubt, you should put the instructions of the recipe in your own words and try not to use too many recipes from one source. If there is still a concern, you should cite the source.
Copyright law states:
A mere listing of ingredients is not protected under copyright law. However, where a recipe or formula is accompanied by substantial literary expression in the form of an explanation or directions, or when there is a collection of recipes as in a cookbook, there may be a basis for copyright protection.
What does this mean? Well, it means that the ingredients and method for cooking a dish, as listed in the recipe, cannot be copyrighted. However, the exact text used to explain the directions as to making the dish can be copyrighted, assuming there is enough there to count as intellectual effort. (For example, the instructions "mix well and serve immediately" surely could not and would not be copyrighted - but five paragraphs detailing preparation could be)
However, if the method of preparation was completely re-written by someone, it doesn't seem to matter if it describes the same method, or an altered method, it's not a copyright violation.
http://everything2.com/index.pl?node...0for%20Recipes