My very first experiment was heating an MRE entree in water, which was easy (took less than 1 hour) and a good use case.
MRE Biscuit on top and Beef Briscuit entree underneath, with just enough water to cover both:
After heating, both piping hot and ready to eat:
Unfortunately, canned pasta and soups are a bit too large to fit.
Those had been one of my original goals.
I subsequently experimented and found that during hot weather, I could easily "cook" those on my van's south-facing dash, which rocks.