Background image in node content
I've used the Dynamic Background module, which has a whole set of advantages for setting up background which vary according to content. At that particular time I used the Context module, which gave me a varied set of options (including content type, path, taxonomy, etc.) and which is very extensible. For your recipes, you could combine with the taxonomy functionality for different types of recipes, or select a particular image for each.

While I don't like using modules for everything, if this is going to be part of your day to day use of the site, I recommend that you choose the simpler solution, so you can try and choose what works better for you.

When you install the Module, you can set up which images you want to use, style the image and the type of behaviour you want for the whole site:



Since you can assign it using CSS, you can set it up for the content area only (#region-content), or whatever indicator you define in Panels. So, you can combine the logic in panels to show a particular background for a content type, or whatever logic you want to assign.