Here's what the United States Copyright Office has to say about recipes:
Mere listings of ingredients as in recipes, formulas, compounds, or prescriptions are not subject
to copyright protection. However, when a recipe or formula is accompanied by substantial
literary expression in the form of an explanation or directions, or when there is a combination
of recipes, as in a cookbook, there may be a basis for copyright protection.
Protection under the copyright law (title 17 of the U.S. Code, section 102) extends only to
“original works of authorship” that are fixed in a tangible form (a copy). “Original” means
merely that the author produced the work by his own intellectual effort, as distinguished from
copying an existing work. Copyright protection may extend to a description, explanation, or
illustration, assuming that the requirements of the copyright law are met.
For information on how to register, see the reverse side of this letter. For further information
on copyright, deposit requirements, and registration procedures, see Circular 1, Copyright
Basics. Deposit requirements depend on whether the work has been published at the time of
registration:
• If the work is unpublished, one complete copy
• If the work was first published in the United States on or after January 1, 1978, two complete
copies of the best edition
• If the work was first published in the United States before January 1, 1978, two complete
copies as first published
• If the work was first published outside the United States, one complete copy of the work as
first published
• If the work is a contribution to a collective work and was published after January 1, 1978,
one complete copy of the best edition of the collective work or a photocopy of the contribution
itself as it was published in the collective work
Copyright protects only the particular manner of an author’s expression in literary, artistic,
or musical form. Copyright protection does not extend to names, titles, short phrases, ideas,
systems, or methods.
Sincerely yours,
Register of Copyrights
Here's the link to the publication:
http://www.copyright.gov/fls/fl122.pdf