I'm working on a very simple recipe database, but it has a slight complication... recipes can in turn be ingredients. For example, a turkey sandwich recipe could contain a mayo recipe, a bread recipe, etc. I just can't figure out how to plan it right... any suggestions?

Try looking at this post. http://www.dbforums.com/t1201563.html In your case, leave out the bag table and include a recursive relationship on the recipe table. The recursive relationship will allow you to make a recipe able to contain many recipes.