If you copy verbatim, absolutely.

Otherwise, consult your lawyer.

That sounds like a "better safe than sorry" situation.

There is a rights and permissions desk at Knopf. Contact them. You will probably have to pay a fee. Copyright infringement comes with a fine. Remember David Ruggieri?

I would by no means act on this statement, but I have been told by a reasonably dependable source that recipes are not subject to copyright protection.

Dianna: you should always give full credit to any recipe author - even if you were just inspired by their recipe. That said, if you change the writing of the recipe, you can use Julia's recipe because you will have made it your own. For instance, specify a particular brand of chocolate, or change Semi-sweet to bittersweet, specify a particular vanilla extract, etc.; add or eliminate salt. Message me if you have further questions.

The U.S. Copyright Office distinguishes between a "recipe" as a list of ingredients (not copyrightable) and the descriptive prose (introductory text, step-by-step instructions) and illustrations that accompany it (copyrightable).

From their website:

"Copyright law does not protect recipes that are mere listings of ingredients. Nor does it protect other mere listings of ingredients such as those found in formulas, compounds, or prescriptions. 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."

So listing exactly the same ingredients as Julia Child's mousse recipe would not violate copyright, but copying her headnote or step-by-step instructions would (whether you credit her or not).

If you paraphrase the instructions, putting them in your own words, there shouldn't be a problem. But it never hurts to run it past the publisher. They deal with issues like this all the time.