If you are truly worried about what to cook with for disaster preparedness, learn to use anything available. MSR has a good multi-fuel stove. It is not the easiest to use, but it works in all conditions I have encountered, from 10,000 feet in 0 degrees F and high winds to jungle at sea level.

Just practice before the disaster happens so you know what you will need. A tin can in a wood fire has always worked for me as well.