One thing I never really covered well on Seeing the Elephant was cooking during the Civil War. I've been a time or two at the Stonewall Jackson house, and in the basement was the kitchen, which always seem to be set with propped-up versions of food of the period. Even fake, it looked all looked good to eat.
This leads me to think what frame of reference Civil War soldiers had when fixing their meals in the field. The first stop on my quest is Civil War Interactive, which has a load of period recipes that were prevalent in Civil War era kitchens. Fannie and Vera have their own page for cooking out-of-doors, which gives some good practical advice about setting up for cooking.
In the soldier's camp, the pickings were a bit leaner. Civil War Home has the guidelines for US Army rations. The Civil War Recipes page does a great job of explaining hardtack and johnnie cakes and provding recipes for them. I also did a post on hardtack about a year ago. Although it is spelled 'Receipt', I think they were shooting for 'Recipe' in this great period cooking resource. But there are some things I wouldn't put into my mouth, like the charcoal tooth powder.