Don’t you dare to think that I did not consider this.. “Space food”. There are products available, that are marketed to be the genuine astronaut food. Freeze dried Ice Cream, berries etc. This stuff is widely available in Internet and in all kind of gadget stores and it’s not even particularly expensive. Just about 4 bucks a packet. (and there probably would be a volume discount when you order full year’s supply)
I bought some of that stuff and it was amazing how ice-creamey it actually was. Even that it was completely dry and therefore felt funny in mouth.
Freeze drying is actually quite old process, but they started to actively develop it during WW2 to be able to ship blood serum to the troops when refrigeration was not always available. In principle it means freezing something in a way that does not crystallize the water and therefore destroy the structure of the subject.
And indeed freeze-drying is one of the many methods of making lightweight, long shelf-life food for space missions.
I could buy some for my mission, but I also have fouond some instructions from Internet about how to freeze-dry food at home without expensive special equipement. I really need to test this and for sure will publish the results here.