Publications International vs Meredith should provide you with the desired clarity. 17 USC 102(b) says
In no case does copyright protection for an original work of
authorship extend to any idea, procedure, process, system, method of
operation, concept, principle, or discovery, regardless of the form in
which it is described, explained, illustrated, or embodied in such
work
The court found that
The identification of ingredients necessary for the preparation of each dish is a
statement of facts. There is no expressive element in each listing;
in other words, the author who wrote down the ingredients for
"Curried Turkey and Peanut Salad" was not giving literary expression
to his individual creative labors. Instead, he was writing down an
idea, namely, the ingredients necessary to the preparation of a
particular dish. "No author may copyright facts or ideas. The
copyright is limited to those aspects of the work
-- termed 'expression'
-- that display the stamp of the author's originality."
and finally
Although the inventions of "Swiss 'n' Cheddar Cheeseballs" and
"Mediterranean Meatball Salad" were at some time original, there can
be no monopoly in the copyright sense in the ideas for producing
certain foodstuffs. Nor can there be copyright in the method one might
use in preparing and combining the necessary ingredients. Protection
for ideas or processes is the purview of patent.
Of course, that precludes copying the author's elegant description of live on the Riviera, which is protected literary work.
