That’s exactly why I built one of these:
My Ammo Can Rocket Stove:
http://www.freerepublic.com/focus/f-chat/2914240/posts
I do like those, and everyone should be prepared with some type of wood stove for cooking.
Whichever stove you use to cook your food with, make sure that you have the pressure cooker, and the pressure canner, and canning supplies.
Among my 15 or so various stoves are the ZZstove, which gives one a somewhat controlled burner, and uses a AA battery, I have rechargeables and a couple of small solar chargers.
http://www.backpackgeartest.org/reviews/Cook%20Gear/Stoves/Zip%20Ztove%20Sierra%20stove/Owner%20Review%20by%20Dawn%20Larsen/
I also have their discontinued, non battery stove which is a backpackers version of the one you built, there are a number of models of those passive, twig burning stoves, that help make the flame more similar to a burner.
Regular kitchen type cooking with fire (not grilling, but boiling and simmering) would be quite an eye opener for most people, it wouldn’t hurt for preppers to try it a couple of times if they are not experienced in it.