On the main page (of http://www.allrecipes.com), just under the search
box near the upper right, there's a link in small type "advanced
search."  That takes you to another page where you can list up to about
5 or 6 (I forget exactly how many) ingredients you want included in the
recipe and 5 or 6 you don't want.  It searches the ingredients in the
recipes.  It worked well for me for cookies -- I can't have butter,
margarine, or shortening, so I listed those in the "not" column along
with cream cheese and sour cream, and put oil in the list of desired
ingredients.

Susan